This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 2000-258159, filed Aug. 28, 2000; and No. 2001-193596, filed Jun. 26, 2001, the entire contents of both of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a photographic lightsensitive material including a spectrally sensitized silver halide photographic emulsion. More particularly, the present invention relates to a photographic lightsensitive material including a silver halide photographic emulsion which exhibits increased light absorption and light absorption intensity and which has sensitizing dyes adsorbed in multilayer form stably even in the presence of an organic solvent.
2. Description of the Related Art
Intensive efforts have been exerted to enhance the sensitivity of silver halide photographic lightsensitive materials. In silver halide photographic emulsions, light sensitivity is obtained as a result of absorption of light incident on the lightsensitive material by a sensitizing dye adsorbed on the surface of silver halide grains and transfer of thus absorbed light energy to silver halide grains. Accordingly, in the spectral sensitization of silver halides, it is contemplated that increasing the light absorption per unit grain surface area of silver halide grains would enable increasing the light energy transferred to silver halides to thereby accomplish enhancement of the spectral sensitivity of silver halide grains. The increasing of the light absorption in the surface of silver halide grains can be accomplished by increasing the adsorption amount of spectral sensitizing dye per unit grain surface area.
However, there is a limit in the adsorption amount of sensitizing dye on the surface of silver halide grains, and it is difficult to adsorb dye chromophores in an amount greater than monolayer saturated adsorption (namely, one-layer adsorption). Therefore, the current situation is that, in the spectral sensitization region, the absorption of incident photons by individual silver halide grains is still low.
Proposals for resolving this matter have been made, which are as follows.
P. B. Gilman, Jr. et al., in Photographic Science and Engineering, vol. 20, no. 3, page 97 (1976), caused the first layer to adsorb a cationic dye and further caused the second layer to adsorb an anionic dye with the use of electrostatic force.
G. B. Bird et al., in U.S. Pat. No. 3,622,316, caused silver halides to adsorb a plurality of dyes in multilayer form and effected sensitization with the contribution of transfer of excitation energy of the Forster type.
Sugimoto et al., in Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-) 63-138341 and JP-A-64-84244, effected spectral sensitization by the energy transfer from luminescent dyes.
R. Steiger et al., in Photographic Science and Engineering, vol. 27, no. 2, page 59 (1983), tried spectral sensitization by the energy transfer from gelatin-substituted cyanine dyes.
Ikegawa et al., in JP-A-61-251842, effected spectral sensitization by the energy transfer from cyclodextrin-substituted dyes.
However, in these proposed methods, the extent of multilayer adsorption of sensitizing dyes on the surface of silver halide grains is actually unsatisfactory with the result that the effect of sensitivity enhancement is extremely poor. Therefore, attempts to realize a substantially effective multilayer adsorption by strengthening the interaction between dye molecules have been made.
It is disclosed in EP No. 838719A2 that increasing of the hydrophobicity of dye molecules would lead to enhancement of the interaction between dye molecules, which is effective in the formation of multilayer adsorption. However, with respect to the thus formed multilayer adsorption, it has become apparent that the state of multilayer adsorption is unstable when an organic solvent is present in the emulsion, especially when a high-boiling organic solvent such as an emulsified substance which is indispensable in the silver halide photographic lightsensitive material is present in the emulsion. Hence, it is an urgent need to develop a technology for stabilizing the state of dye multilayer adsorption.
Parton et al. (JP-A-2000-89406) describe that the stability of multilayer adsorption against external factors such as a dispersion of color forming coupler can be enhanced only when dye layers of the dye multilayer adsorption are bonded with each other through two or more noncovalent attractive forces. However, this stabilization effect is not so high, and, when employed in practicable silver halide photographic lightsensitive materials containing a high-boiling organic solvent, it is difficult to realize such a stability as can endure practical use. Furthermore, substituents are limited, so that the variety of available dyes is limited.
In contrast, it is known that a multilayer adsorption based on a combination of cationic dyes is effective in the enhancements of light absorption and sensitivity. However, the stability of multilayer adsorption is still poor against external factors such as a dispersion of color forming coupler.
The development processing time of color negative lightsensitive materials has been shortened by Kodak processing C-41 introduced in 1972. The wet processing time, not including any drying step, required by the processing is 17 min 20 sec. The processor CN-16FA introduced in the mini-lab market by Fuji Photo Film Co., Ltd. in recent years has enabled shortening the wet processing time to 8 min 15 sec. However, the current situation is that the shop processing and finishing, even speediest in view of the contemporary processing time level, still requires about 30 min to thereby compel a majority of users to make two visits to the photograph shop. Thus, further shortening of development processing time is desired in order to meet the demand for one visit to photograph shop from users.
Reduction of development time by raising the developing temperature of color developer has been investigated in order to attain shortening of color development time. However, the intended shortening is not easy because of the occurrence of sensitivity lowering and because of the increase of photographic property change due to processing variation. Improving the ratio of sensitivity/graininess by effecting a short-time processing is disclosed in JP-A-62-192740. However, the demanded level has not yet been attained thereby. Therefore, there is still a strong demand for improvement of the ratio of sensitivity/graininess and for suppression of the photographic property change due to processing variation.
It is an object of the present invention to provide a photographic lightsensitive material including a silver halide photographic emulsion which is highly sensitive and wherein sensitizing dyes are contained in multilayer form stably even in the presence of an organic solvent.
The inventors have made extensive and intensive studies with a view toward attaining the above object. As a result, it has been found that the stability of dye multilayer adsorption can be dramatically enhanced by the use of specified emulsified substance to thereby attain an effective enhancement of spectral sensitivity even in practical silver halide photographic lightsensitive materials wherein a high-boiling organic solvent is present.
Specifically, although, with respect to highly hydrophobic dyes, it is contemplated that the state of multilayer adsorption is unstable because of their high solubility in organic solvents, there is no report regarding the interrelationship between properties of high-boiling organic solvents and stability of multilayer adsorption, and there is no knowledge as to the interrelationship between properties of surfactants required for dispersing high-boiling organic solvents, or types of color forming couplers dissolved in high-boiling organic solvents, and stability of multilayer adsorption. Noting these, studies have been conducted. As a result, the present invention characterized by the following constitutions has been completed.
(1) A silver halide photographic lightsensitive material comprising at least one silver halide photographic emulsion layer containing a silver halide photographic emulsion prepared by mixing a dispersion of silver halide grains, the silver halide grains exhibiting such spectral absorption maximum wavelength and light absorption intensity that, when the spectral absorption maximum wavelength is less than 500 nm, the light absorption intensity is 60 or more, while when the spectral absorption maximum wavelength is 500 nm or more, the light absorption intensity is 100 or more, with an emulsified dispersion, wherein the silver halide photographic emulsion, when agitated at 40xc2x0 C. for 30 min, exhibits a variation of absorption spectrum integrated intensity ranging from 400 nm to 700 nm of 10% or less.
(2) A silver halide photographic lightsensitive material comprising at least one silver halide photographic emulsion layer prepared by mixing a dispersion of silver halide grains, the silver halide grains exhibiting such spectral absorption maximum wavelength and light absorption intensity that, when the spectral absorption maximum wavelength is less than 500 nm, the light absorption intensity is 60 or more, while when the spectral absorption maximum wavelength is 500 nm or more, the light absorption intensity is 100 or more, with an emulsified dispersion, wherein the silver halide photographic emulsion layer, when the silver halide photographic lightsensitive material is aged at 60xc2x0 C. in 30% humidity for 3 days, exhibits a variation of absorption spectrum integrated intensity ranging from 400 nm to 700 nm of 10% or less.
(3) A silver halide photographic lightsensitive material comprising, on one side of a support, photographic constituting element layers composed of a unit red-sensitive layer, a unit green-sensitive layer, a unit blue-sensitive layer and a nonlightsensitive layer, wherein each of the unit red-sensitive layer, unit green-sensitive layer and unit blue-sensitive layer comprises two or more layers differing in speed, and wherein, in at least one of the unit red-sensitive layer, unit green-sensitive layer and unit blue-sensitive layer, at least one high-speed-side emulsion layer contains the silver halide photographic emulsion, prepared by mixing the dispersion of silver halide grains with the eulsified dispersion, according to item (1) or (2), and a low-speed-side emulsion layer adjacent to the high-speed-side emulsion layer exhibits a speed of 60% or more based on that of the high-speed-side emulsion layer.
(4) A silver halide photographic lightsensitive material comprising, on one side of a support, photographic constituting element layers composed of a unit red-sensitive layer, a unit green-sensitive layer, a unit blue-sensitive layer and a nonlightsensitive layer, wherein at least one of the photographic constituting element layers contains the silver halide photographic emulsion, prepared by mixing the dispersion of silver halide grains with the emulsified dispersion, according to item (1) or (2), and whose total silver content is in the range of 0.1 to 7.0 g/m2.
(5) The silver halide photographic lightsensitive material according to any of items (1) to (4), wherein the emulsified dispersion contains a surfactant whose critical micell concentration is 4.0xc3x9710xe2x88x923 mol/L or less, the surfactant content being 0.01% by mass or more based on the silver halide photographic emulsion layer.
(6) The silver halide photographic lightsensitive material according to any of items (1) to (5), wherein the emulsified dispersion contains a high-boiling organic solvent whose dielectric constant is 7.0 or less, the content of the high-boiling organic solvent being in the range of 0.05 to 10% by mass based on the silver halide photographic emulsion layer.
(7) The silver halide photographic lightsensitive material according to any of items (1) to (6), wherein the emulsified dispersion contains a compound of the formula 1: 
where R1 represents a tertiary alkyl group or an aryl group; R2 represents a hydrogen atom, a halogen atom (F, Cl, Br or I), an alkoxy group, an aryloxy group, an alkyl group or a dialkylamino group; R3 represents a group capable of effecting a substitution on a benzene ring; X represents a hydrogen atom or a heterocycle capable of being eliminated by a coupling reaction with an oxidation product of aromatic primary amine developing agent and capable of bonding at a nitrogen atom with a coupling active site; and L is an integer of 0 to 4, provided that, when L is two or more, two or more R3 groups may be identical with or different from each other.
(8) The silver halide photographic lightsensitive material according to any of items (1) to (7), wherein sensitizing dyes are adsorbed in multilayer form on surfaces of the silver halide grains.
(9) The silver halide photographic lightsensitive material according to item (8), wherein, among the sensitizing dyes adsorbed in multilayer form, a second-layer dye has an excitation energy which is transferred to a first-layer dye at an efficiency of 10% or more.
(10) The silver halide photographic lightsensitive material according to item (8), wherein, among the sensitizing dyes adsorbed in multilayer form, both a first-layer dye and a second-layer dye exhibit a J-band absorption.
(11) The silver halide photographic lightsensitive material according to item (9), wherein both the first-layer dye and the second-layer dye exhibit a J-band absorption.
With respect to spectral variation, it is preferred that the silver halide photographic emulsion, when agitated at 40xc2x0 C. for 30 min, exhibit a variation of absorption spectrum integrated intensity ranging from 400 nm to 700 nm of 10% or less, or a variation of absorbance maximum of 10% or less. Also, it is preferred that the silver halide photographic emulsion layer, when the silver halide photographic lightsensitive material is aged at 60xc2x0 C. in 30% humidity for 3 days, exhibit a variation of absorption spectrum integrated intensity ranging from 400 nm to 700 nm of 10% or less, or a variation of absorbance maximum of 10% or less.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.
The present invention will be described in detail below.
The present invention relates to a silver halide photographic lightsensitive material containing silver halide grains sensitized by dyes, particularly a high-speed silver halide photographic lightsensitive material containing a silver halide photographic emulsion which has sensitizing dyes adsorbed in multilayer form stably even in the presence of an organic solvent.
In the present invention, the light absorption intensity refers to a light absorption area intensity per grain surface area realized by a sensitizing dye. It is defined as an integral value, over wave number (cmxe2x88x921), of optical density Log (Io/(Io-I)), wherein Io represents the quantity of light incident on each unit surface area of grains and I represents the quantity of light absorbed by the sensitizing dye on the surface. The range of integration is from 5000 cmxe2x88x921 to 35,000 cmxe2x88x921.
The silver halide photographic emulsion of the present invention (hereinafter also simply referred to as xe2x80x9cemulsion of the present inventionxe2x80x9d) is prepared by mixing a dispersion of silver halide grains, the dispersion of silver halide grains exhibiting such spectral absorption maximum wavelength and light absorption intensity that, when the spectral absorption maximum wavelength is less than 500 nm, the light absorption intensity is 60 or more, while when the spectral absorption maximum wavelength is 500 nm or more, the light absorption intensity is 100 or more, with an emulsified dispersion. The silver halide photographic lightsensitive material of the present invention, in its one embodiment, includes at least one silver halide photographic emulsion layer containing this emulsion. In the present invention, the emulsion of the present invention preferably contains the above silver halide grains in a ratio of xc2xd or more to the total projected area of silver halide grains. With respect to grains whose spectral absorption maximum wavelength is 500 nm or more, the light absorption intensity thereof is preferably 150 or more, more preferably 170 or more, and most preferably 200 or more. With respect to grains whose spectral absorption maximum wavelength is less than 500 nm, the light absorption intensity thereof is preferably 90 or more, more preferably 100 or more, and most preferably 120 or more. The light absorption intensity thereof, although there is no particular upper limit, is preferably 2000 or less, more preferably 1000 or less, and most preferably 500 or less.
With respect to grains whose spectral absorption maximum wavelength is less than 500 nm, it is preferred that the spectral absorption maximum wavelength be 350 nm or more.
As one method of measuring the light absorption intensity, there can be mentioned the method of using a microscopic spectrophotometer. The microscopic spectrophotometer is a device capable of measuring an absorption spectrum of minute area, whereby a transmission spectrum of each grain can be measured. With respect to the measurement of an absorption spectrum of each grain by the microscopic spectro-photometry, reference can be made to the report of Yamashita et al. (page 15 of Abstracts of Papers presented before the 1996 Annual Meeting of the Society of Photographic Science and Technology of Japan). The absorption intensity per grain can be determined from the absorption spectrum. Because the light transmitted through grains is absorbed by two surfaces, i.e., upper surface and lower surface, however, the absorption intensity per grain surface area can be determined as xc2xd of the absorption intensity per grain obtained in the above manner. At that time, although the interval for absorption spectrum integration is from 5000 cmxe2x88x921 to 35,000 cmxe2x88x921 in view of the definition of light absorption intensity, experimentally, it is satisfactory to integrate over an interval including about 500 cmxe2x88x921 after and before the interval of absorption by sensitizing dye.
The light absorption intensity is a value unequivocally determined from the oscillator strength and number of adsorbed molecules per area with respect to the sensitizing dye. If, with respect to the sensitizing dye, the oscillator strength, dye adsorption amount and grain surface area are measured, these can be converted into the light absorption intensity.
The oscillator strength of sensitizing dye can be experimentally determined as a value proportional to the absorption area intensity (optical densityxc3x97cmxe2x88x921 of sensitizing dye solution, so that the light absorption intensity can be calculated within an error of about 10% by the formula:
0.156xc3x97Axc3x97B/C
wherein A represents the absorption area intensity per M of dye (optical densityxc3x97cmxe2x88x921), B represents the adsorption amount of sensitizing dye (mol/molAg) and C represents the grain surface area (m2/molAg).
Calculation of the light absorption intensity through this formula gives substantially the same value as the integral value, over wave number (cmxe2x88x921), of light absorption intensity (Log (Io/(Io-I))) measured in accordance with the aforementioned definition.
For increasing the light absorption intensity, there can be employed any of the method of adsorbing more than one layer of dye chromophore on grain surfaces, the method of increasing the molecular extinction coefficient of dye and the method of decreasing a dye-occupied area. Of these, the method of adsorbing more than one layer of dye chromophore on grain surfaces is preferred.
The expression xe2x80x9cadsorption of more than one layer of dye chromophore on grain surfacesxe2x80x9d used herein means the presence of more than one layer of dye bound in the vicinity of silver halide grains. Thus, it is meant that dye present in a dispersion medium is not contained. Even if a dye chromophore is connected with a substance adsorbed on grain surfaces through a covalent bond, when the connecting group is so long that the dye chromophore is present in the dispersion medium, the effect of increasing the light absorption intensity is slight and hence it is not regarded as the more than one layer adsorption. Further, in the so-called multi-layer adsorption wherein more than one layer of dye chromophore is adsorbed on grain surfaces, it is required that a spectral sensitization be brought about by a dye not directly adsorbed on grain surfaces. For meeting this requirement, the transfer of excitation energy from the dye not directly adsorbed on silver halide to the dye directly adsorbed on grains is inevitable. Therefore, when the transfer of excitation energy must occur in more than 10 stages, the final transfer efficiency of excitation energy will unfavorably be low. As an example thereof, there can be mentioned such a case that, as experienced in the use of polymer dyes of, for example, JP-A-2-113239, most of dye chromophore is present in a dispersion medium, so that more than 10 stages are needed for the transfer of excitation energy.
In the present invention, the number of dye chromophores per dye molecule is preferably in the range of 1 to 3, more preferably 1 to 2.
The terminology xe2x80x9cchromophorexe2x80x9d used herein means an atomic group which is the main cause of molecular absorption bands as described on pages 985 and 986 of Physicochemical Dictionary (4th edition, published by Iwanami Shoten, Publishers in 1987), for example, any atomic group selected from among Cxe2x95x90C, Nxe2x95x90N and other atomic groups having unsaturated bonds.
Examples thereof include a cyanine dye, a styryl dye, a hemicyanine dye, a merocyanine dye, a trinuclear merocyanine dye, a tetranuclear merocyanine dye, a rhodacyanine dye, a complex cyanine dye, a complex merocyanine dye, an allopolar dye, an oxonol dye, a hemioxonol dye, a squarium dye, a croconium dye, an azamethine dye, a coumarin dye, an allylidene dye, an anthraquinone dye, a triphenylmethane dye, an azo dye, an azomethine dye, a spiro compound, a metallocene dye, a fluorenone dye, a fulgide dye, a perillene dye, a phenazine dye, a phenothiazine dye, a quinone dye, an indigo dye, a diphenylmethane dye, a polyene dye, an acridine dye, an acridinone dye, a diphenylamine dye, a quinacridone dye, a quinophthalone dye, a phenoxazine dye, a phthaloperillene dye, a porphyrin dye, a chlorophyll dye, a phthalocyanine dye and a metal complex dye.
Of these, there can preferably be employed polymethine chromophores such as a cyanine dye, a styryl dye, a hemicyanine dye, a merocyanine dye, a trinuclear merocyanine dye, a tetranuclear merocyanine dye, a rhodacyanine dye, a complex cyanine dye, a complex merocyanine dye, an allopolar dye, an oxonol dye, a hemioxonol dye, a squarium dye, a croconium dye and an azamethine dye. More preferred are a cyanine dye, a merocyanine dye, a trinuclear merocyanine dye, a tetranuclear merocyanine dye and a rhodacyanine dye. Most preferred are a cyanine dye, a merocyanine dye and a rhodacyanine dye. A cyanine dye is optimally employed.
Details of these dyes are described in, for example, F. M. Harmer, xe2x80x9cHeterocyclic Compounds-Cyanine Dyes and Related Compoundsxe2x80x9d, John Wiley and Sons, New York, London, 1964 and D. M. Sturmer, xe2x80x9cHeterocyclic Compounds-Special topics in heterocyclic chemistryxe2x80x9d, chapter 18, section 14, pages 482 to 515, John Wiley and Sons, New York, London, 1977. As general formulae for preferred dyes, there can be mentioned those given on pages 32 to 36 of U.S. Pat. No. 5,994,051 and pages 30 to 34 of U.S. Pat. No. 5,747,236. With respect to the general formulae for the cyanine dye, merocyanine dye and rhodacyanine dye, those shown in U.S. Pat. No. 5,340,694, columns 21 to 22, (XI), (XII) and (XIII), are preferred. In the formulae, the numbers n12, n15, n17 and n18 are not limited as long as each of these is an integer of 0 or greater (preferably, 4 or less).
The adsorption of a dye chromophore on silver halide grains is preferably carried out in at least 1.5 layers, more preferably at least 1.7 layers, and most preferably at least 2 layers. Although there is no particular upper limit, the number of layers is preferably 10 or less, more preferably 5 or less.
The expression xe2x80x9cadsorption of more than one layer of chromophore on silver halide grain surfacesxe2x80x9d used herein means that, as aforementioned, dyes bound in the vicinity of silver halide grains are present in the form of more than one layer. The expression more specifically means that the adsorption amount of dye chromophore per area is greater than a one-layer saturated coating amount, this one-layer saturated coating amount defined as the saturated adsorption amount per area attained by a dye which exhibits the smallest dye-occupied area on silver halide grain surfaces among the sensitizing dyes added to the emulsion. The number of adsorption layers means the adsorption amount evaluated on the basis of one-layer saturated coating amount. With respect to dyes having dye chromophores connected to each other by covalent bonds, the dye-occupied area of unconnected individual dyes can be employed as the basis.
The dye-occupied area can be determined from an adsorption isothermal line showing the relationship between isolated dye concentration and adsorbed dye amount, and a grain surface area. The adsorption isothermal line can be determined with reference to, for example, A. Herz et al. xe2x80x9cAdsorption from Aqueous Solutionxe2x80x9d, Advances in Chemistry Series, No. 17, page 173 (1968).
The adsorption amount of a sensitizing dye onto emulsion grains can be determined by two methods. The one method comprises centrifuging an emulsion having undergone a dye adsorption to thereby separate the emulsion into emulsion grains and a supernatant aqueous solution of gelatin, determining an unadsorbed dye concentration from the measurement of spectral absorption of the supernatant, and subtracting the same from the added dye amount to thereby determine the adsorbed dye amount. The other method comprises depositing emulsion grains, drying the same, dissolving a given mass of deposit in a 1:1 mixture of an aqueous solution of sodium thiosulfate and methanol, and effecting a spectral absorption measurement thereof to thereby determine the adsorbed dye amount. When a plurality of sensitizing dyes are employed, the absorption amount of each dye can be determined by high-performance liquid chromatography or other techniques. With respect to the method of determining the dye absorption amount by measuring the dye amount in a supernatant, reference can be made to, for example, W. West et al., Journal of Physical Chemistry, vol. 56, page 1054 (1952). However, even unadsorbed dye may be deposited when the addition amount of dye is large, so that it has been experienced that an accurate absorption amount is not always obtained by the method of measuring the dye concentration of the supernatant. On the other hand, in the method in which the absorption amount of dye is determined by dissolving deposited silver halide grains, the deposition velocity of emulsion grains is overwhelmingly faster, so that grains and deposited dye can easily be separated from each other. Thus, only the amount of dye adsorbed on grains can accurately be determined. Therefore, this method is most reliable as a means for determining the dye absorption amount.
The adsorption amount of photographically useful compounds on grains, although can be measured in the same manner as in the adsorption of sensitizing dyes, is preferably measured by the quantitative method based on high-performance liquid chromatography, rather than the quantitative method based on spectral absorption, from the viewpoint that the absorption in visible light region is weak.
As one method of measuring the surface area of silver halide grains, there can be employed the method wherein a transmission electron micrograph is taken according to the replica method and wherein the configuration and size of each individual grain are measured and calculated. In this method, the thickness of tabular grains is calculated from the length of shadow of the replica. With respect to the method of taking a transmission electron micrograph, reference can be made to, for example, Denshi Kenbikyo Shiryo Gijutsu Shu (Electron Microscope Specimen Technique Collection) edited by the Kanto Branch of the Society of Electron Microscope of Japan and published by Seibundo Shinkosha in 1970 and P. B. Hirsch, xe2x80x9cElectron Microscopy of Thin Crystalsxe2x80x9d, Buttwrworths, London (1965).
As the other method, reference can be made to, for example, A. M. Kragin et al., Journal of Photographic Science, vol. 14, page 185 (1966), J. F. Paddy, Transactions of the Faraday Society, vol., 60, page 1325 (1964), S. Boyer et al., Journal de Chimie Physique et de Physicochimie biologique, vol., 63, page 1123 (1963), W. West et al., Journal of Physical Chemistry, vol., 56, page 1054 (1952), and E Klein et al., xe2x80x9cScientific Photographyxe2x80x9d, International Coloquium, edited by H. Sauvenier, Liege (1959).
Experimentally, each of the dye-occupied area can be determined from the above methods. Because the molecule-occupied area of sensitizing dye is around 80xc3x9710xe2x88x9220 m2, however, the number of adsorption layers can be briefly estimated by determining the dye-occupied area of all dyes as 80xc3x9710xe2x88x9220 m2.
When a multi-layer of dye chromophore is adsorbed on silver halide grains in the present invention, although the reduction potentials and oxidation potentials of the dye chromophore of the first layer, namely the layer directly adsorbed on silver halide grains, vs. the dye chromophore of the second et seq. layers are not particularly limited, it is preferred that the reduction potential of the dye chromophore of the first layer be noble to the remainder of the reduction potential of the dye chromophore of the second et seq. layers minus 0.2V.
Although the reduction potential and oxidation potential can be measured by various methods, the measurement is preferably carried out by the use of phase discrimination second harmonic a.c. polarography, whereby accurate values can be obtained. The method of measuring potentials by the use of phase discrimination second harmonic a.c. polarography is described in Journal of Imaging Science, vol. 30, page 27 (1986).
The dye chromophore of the second et seq. layers preferably consists of a luminescent dye. With respect to the type of luminescent dye, those having the skeletal structure of dye for use in dye laser are preferred. The luminescence yield of second-layer dye, when present alone in gelatin, is 0.1 or more, preferably 0.3 or more, more preferably 0.5 or more, and most preferably 0.7 or more. The luminescence of second-layer dye per se (probability of second-layer dye being excited followed by radiation deactivation thereof), when present as a second-layer dye as a result of multilayer adsorption, is 0.5 or less, preferably 0.3 or less, more preferably 0.1 or less, and most preferably 0.05 or less. These are edited in, for example, Mitsuo Maeda, Laser Kenkyu (Laser Research), vol. 8, pp. 694, 803 and 958 (1980) and ditto, vol. 9, page 85 (1981), and F. Sehaefer, xe2x80x9cDye Lasersxe2x80x9d, Springer (1973).
Moreover, the absorption maximum wavelength of dye chromophore of the first layer in the silver halide photographic lightsensitive material is preferably greater than that of dye chromophore of the second et seq. layers. Further, preferably, the light emission of dye chromophore of the second et seq. layers and the absorption of dye chromophore of the first layer overlap each other. Also, it is preferred that the dye chromophore of the first layer form a J-association product. Still further, for exhibiting absorption and spectral sensitivity within a desired wavelength range, it is preferred that the dye chromophore of the second et seq. layers also form a J-association product.
In the present invention, it is preferred that the excitation energy of second-layer dye, among the sensitizing dyes adsorbed on silver halide grain surfaces, be transferred to the first-layer dye at an efficiency of 10% or more.
In the present invention, the expression xe2x80x9cthe excitation energy of second-layer dye is transferred to the first-layer dye at an efficiency of 10% or morexe2x80x9d means that the ratio of increase of the speed of the emulsion having two-layer adsorption over the speed of the emulsion having adsorption of a first-layer dye only is 10% or more based on the ratio of increase of the light absorption intensity of the emulsion having two-layer adsorption over the light absorption intensity of the emulsion having adsorption of a first-layer dye only. This efficiency is a measure of the effect of how much the light absorption intensity increased by the lightsensitive material of the present invention contributes to speed increase.
The efficiency of transfer of the excitation energy of second-layer dye to first-layer dye is more preferably 30% or more, still more preferably 60% or more, and most preferably 90% or more. The energy transfer efficiency from second-layer dye to first-layer dye can be determined as [spectral sensitization ratio at the excitation of second-layer dye]/[spectral sensitization ratio at the excitation of first-layer dye].
The meanings of terminologies employed in the present invention are set forth below.
Dye-occupied area: Area occupied by each molecule of dye, which can experimentally be determined from adsorption isothermal lines. With respect to dyes having dye chromophores connected to each other by covalent bonds, the dye-occupied area of unconnected individual dyes can be employed as the basis. In brief, 80xc3x9710xe2x88x9220 m2.
One-layer saturated coating amount: Dye adsorption amount per grain surface area at one-layer saturated coating, which is the inverse number of the smallest dye-occupied area exhibited by added dyes.
Multi-layer adsorption: In such a state that the adsorption amount of dye chromophore per grain surface area is greater than the one-layer saturated coating amount.
Number of adsorption layers: Adsorption amount of dye chromophore per grain surface area on the basis of one-layer saturated coating amount.
In the present invention, it is preferred that the intergranular distribution of light absorption intensity be narrow. The intergranular distribution of light absorption intensity can be expressed as a variation coefficient of the light absorption intensities of 100 or more grains measured at random by the use of microspectroscopy. The variation coefficient can be calculated by the formula: 100xc3x97standard deviation/average (%). Because the light absorption intensity is a value which is proportional to the adsorption amount of dye, the intergranular distribution of light absorption intensity can be expressed as the intergranular distribution of dye adsorption amount. The variation coefficient of intergranular distribution of light absorption intensity is preferably 60% or less, more preferably 30% or less, and most preferably 10% or less.
The variation coefficient of intergranular distribution of interval between the smallest wavelength and the largest wavelength each exhibiting 50% of the maximum Amax of absorption of sensitizing dye is preferably 30% or less, more preferably 10% or less, and most preferably 5% or less.
With respect to the absorption maximum wavelength of sensitizing dye of each individual grain, preferably 70% or more, more preferably 90% or more, in terms of projected area of grains have the absorption maximum within a wavelength range of 10 nm or less. It is more desirable that, with respect to the absorption maximum wavelength of sensitizing dye of each individual grain, preferably 50% or more, more preferably 70% or more, and most preferably 90% or more, in terms of projected area of grains have the absorption maximum within a wavelength range of 5 nm or less.
Although it is known that the intergranular distribution of light absorption intensity (adsorption amount of dye) is uniformized in accordance with an increase of dye adsorption amount when adsorption sites are limited to silver halide grain surfaces, it has been found that, in the multilayer adsorption of the present invention, there is no limit in adsorption sites if the adsorption in the form of two or more layers is possible, and that an intergranular distribution is very likely to occur, for example, some grains having monolayer adsorption while other grains having three-layer adsorption. As a result of an analysis, it has become apparent that, when the ratio of the interactive energy between second-layer dyes to the total adsorption energy of second-layer dyes is increased (the ratio of the interactive energy between first-layer and second-layer dye molecules decreased relatively), an intergranular nonuniformity of dye adsorption amount of a multilayer adsorption system is likely to occur. The interactive energy between first-layer and second-layer dye molecules is preferably 20% or more, more preferably 40% or more, based on the total adsorption energy of second-layer dyes.
In the multilayer adsorption of the present invention, the total adsorption energy is 5 kcal/mol or more, preferably 10 kcal/mol or more, and more preferably 15 kcal/mol or more.
For strengthening the interaction between first-layer dye and second-layer dye, it is preferred to utilize the electrostatic interaction, Van der Waals interaction, hydrogen bond, coordinate bond and composite interactive force thereof between first-layer and second-layer dye molecules. Although it is preferred that the main interaction between second-layer dyes be the Van der Waals interaction between dye chromophores, it is also preferred to utilize the electrostatic interaction, Van der Waals interaction, hydrogen bond, coordinate bond and composite interactive force thereof as long as the above preferred relationship is satisfied.
The ratio of the interactive energy between first-layer and second-layer dye molecules to the total adsorption energy of second-layer dyes, although actually determining it is difficult, can be presumed by the use of the method of computer chemistry such as computation of molecular force fields.
Experimentally, the ratio can be estimated by measuring the cohesive energies between second-layer dye molecules and between first-layer dye and second-layer dye molecules and introducing the measured cohesive energies in the formula: 100xc3x97[cohesive energy between first-layer dye and second-layer dye molecules]/[cohesive energy between second-layer dye molecules+cohesive energy between first-layer dye and second-layer dye molecules]. The cohesive energy can be determined by the use of, for example, the method of Matsubara, Tanaka et al. (Journal of the Society of Photographic Science and Technology of Japan, vol. 52, page 395 (1989)).
With respect to the emulsion containing silver halide photographic emulsion grains wherein, when the spectral absorption maximum wavelength is less than 500 nm, the light absorption intensity is 60 or more, while when the spectral absorption maximum wavelength is 500 nm or more, the light absorption intensity is 100 or more, the interval between the smallest wavelength and the largest wavelength each exhibiting 50% of spectral sensitivity maximum Smax and maximum of spectral absorption factor Amax by sensitizing dye is preferably 120 nm or less, more preferably 100 nm or less.
The interval between the smallest wavelength and the largest wavelength each exhibiting 80% of spectral sensitivity maximum Smax and maximum of spectral absorption factor Amax is preferably in the range of 20 nm to 100 nm, more preferably to 80 nm, and most preferably to 50 nm.
The interval between the smallest wavelength and the largest wavelength each exhibiting 20% of spectral sensitivity maximum Smax and maximum of spectral absorption factor Amax is preferably 180 nm or less, more preferably 150 nm or less, still more preferably 120 nm or less, and most preferably 100 nm or less.
The largest wavelength exhibiting a spectral absorption factor equal to 50% of spectral sensitivity maximum Smax or maximum of spectral absorption factor Amax is preferably in the range of 460 to 510 nm, or 560 to 610 nm, or 640 to 730 nm.
As aforementioned, the present invention has been completed on the basis of findings as to the interrelationship between an emulsified dispersion and the stability of dye multilayer adsorption. It is preferred that a high-boiling organic solvent, a 0surfactant, a compound which is reactive with developing agent oxidation products, or a combination thereof be contained in the emulsified dispersion mixed in the emulsion of the present invention. It is especially preferred that a coupler which induces a coupling reaction with an oxidation product of aromatic primary amine developing agent to thereby effect coloring, or a compound which reacts with an oxidation product of aromatic primary amine developing agent to thereby release a dye, a compound having a development inhibiting function and other photographically useful compounds be contained in the emulsified dispersion.
The surfactant which can be employed in the present invention, although not limited as long as the critical micell concentration thereof is 4.0xc3x9710xe2x88x923 mol/L or less, is preferably one capable of functioning as a dispersant for high-boiling organic solvents. More preferably, the surfactant for use in the present invention is an anionic surfactant such as a sulfoalkyl or a sulfoaryl, a nonionic surfactant such as an alkylpolyethylene oxide, or a betaine surfactant such as a sulfoalkylammonium. Further, use can be made of a polymer surfactant comprising a polymer having functional groups bonded thereto. Herein, the critical micell concentration refers to the concentration at which the surface tension is the lowest on a concentration/surface tension curve as obtained by first preparing solutions of varied surfactant concentrations, subsequently measuring surface tensions of the solutions with the use of surface tensiometer A3 manufactured by Kyowa Kagaku K.K. and thereafter plotting surface tension values against an axis of concentration logarithm. The critical micell concentration is the lowest concentration allowing the surfactant to form micells. The lower this value, the greater the surface activating capability.
In the present invention, the content of surfactant in the emulsion is preferably 0.01% by mass or more, more preferably 0.02% by mass or more.
Examples of surfactants for use in the present invention will be set out below, to which, however, the present invention is naturally in no way limited:
The high-boiling organic solvent which can be employed in the present invention is preferably one with a dielectric constant of 7.0 or less. It can be selected from among high-boiling organic solvents whose boiling point is about 175xc2x0 C. or higher at atmospheric pressure, such as phthalic acid esters, phosphoric acid esters, phosphonic acid esters, benzoic acid esters, fatty acid esters, amides, phenols, alcohols, ethers, carboxylic acids, N,N-dialkylanilines, trialkylamines, hydrocarbons, oligomers and polymers. When two or more high-boiling organic solvents are used in mixture, the mixture, if exhibiting a dielectric constant of 7.0 or less, corresponds to the above high-boiling organic solvent of 7.0 or less dielectric constant.
These high-boiling organic solvents with a dielectric constant of 7.0 or less can be used in mixture with a high-boiling organic solvent with a dielectric constant of greater than 7.0. In that case as well, the mixture, if exhibiting a dielectric constant of 7.0 or less, corresponds to the above high-boiling organic solvent of 7.0 or less dielectric constant. Herein, the dielectric constant refers to a specific dielectric constant to vacuum as measured by the transformer bridge method at a measuring temperature of 25xc2x0 C. and at a measuring frequency of 10 kHz with the use of dielectric constant meter, model TRS-10T, manufactured by Ando Denki. The dielectric constant of organic solvent interrelates with the square of dipole moment of organic solvent molecules, that is, indicates the magnitude of polarity of molecules. Generally, molecules of high dielectric constant have high polarity.
The high-boiling organic solvents preferably employed in the present invention are those of 7.0 or less dielectric constant, represented by the following general formulae [S-1] to [S-8]. 
In the formula [S-1], each of R1, R2 and R3 independently represents an alkyl group, a cycloalkyl group or an aryl group. In the formula [S-2], each of R4 and R5 independently represents an alkyl group, a cycloalkyl group or an aryl group; R6 represents a halogen atom (F, Cl, Br or I; the same shall apply hereinafter), an alkyl group, an alkoxy group, an aryloxy group or an alkoxycarbonyl group; and a is an integer of 0 to 3, provided that, when a is 2 or greater, a plurality of R6 groups may be identical with or different from each other.
In the formula [S-3], Ar represents an aryl group; b is an integer of 1 to 6; and R7 represents a b-valent hydrocarbon group or a group of hydrocarbons coupled with each other through an ether bond. In the formula [S-4], R8 represents an alkyl group or a cycloalkyl group; c is an integer of 1 to 6; and R9 represents a c-valent hydrocarbon group or a group of hydrocarbons coupled with each other through an ether bond. In the formula [S-5], d is an integer of 2 to 6; R10 represents a d-valent hydrocarbon group (provided that an aromatic group is excluded); and R11 represents an alkyl group, a cycloalkyl group or an aryl group. In the formula [S-6], each of R12, R13 and R14 independently represents an alkyl group, a cycloalkyl group or an aryl group, provided that R12 and R13, or R13 and R14 may be bonded with each other to thereby form a ring.
In the formula [S-7], R15 represents an alkyl group, a cycloalkyl group, an alkoxycarbonyl group, an alkoxysulfonyl group, an arylsulfonyl group, an aryl group or a cyano group; R16 represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group or an aryloxy group; and e is an integer of 0 to 3, provided that, when e is 2 or greater, a plurality of R16 groups may be identical with or different from each other.
In the formula [S-8], each of R17 and R18 independently represents an alkyl group, a cycloalkyl group or an aryl group; R19 represents a halogen atom, an alkyl group, a cycloalkyl group or an aryloxy group; and f is an integer of 0 to 4, provided that, when f is 2 or greater, a plurality of R19 groups may be identical with or different from each other. In the formulae [S-1] to [S-8], when each of R1 to R6, R8 and R11 to R19 is an alkyl group or a group containing an alkyl group, the alkyl group may be in the form of a linear or a branched chain, may contain an unsaturated bond, and may have a substituent. As the substituent, there can be mentioned, for example, a halogen atom, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, a hydroxyl group, an acyloxy group or an epoxy group.
In the formulae [S-1] to [S-8], when each of R1 to R6, R8 and R11 to R19 is a cycloalkyl group or a group containing a cycloalkyl group, the cycloalkyl group may contain an unsaturated bond in its 3 to 8-membered ring, and may have a substituent or a crosslink group. As the substituent, there can be mentioned, for example, a halogen atom, a hydroxyl group, an acyl group, an aryl group, an alkoxy group, an epoxy group or an alkyl group. As the crosslink group, there can be mentioned, for example, methylene, ethylene or isopropylidene.
In the formulae [S-1] to [S-8], when each of R1 to R6, R8 and R11 to R19 is an aryl group or a group containing an aryl group, the aryl group may be substituted with a substituent such as a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group or an alkoxycarbonyl group. In the formulae [S-3], [S-4] and [S-5], when each of R7, R9 and R10 is a hydrocarbon group, the hydrocarbon group may contain a cyclic structure (for example, a benzene ring, a cyclopentane ring or a cyclohexane ring) or an unsaturated bond, and further may have a substituent. As the substituent, there can be mentioned, for example, a halogen atom, a hydroxyl group, an acyloxy group, an aryl group, an alkoxy group, an aryloxy group or an epoxy group. In the formula [S-1], each of R1, R2 and R3 represents an alkyl group having 1 to 24 (preferably 4 to 18) carbon atoms (total number of carbon atoms in each molecule) (for example, n-butyl, 2-ethylhexyl, 3,3,5-trimethylhexyl, n-dodecyl, n-octadecyl, benzyl, oleoyl, 2-chloroethyl, 2,3-dichloropropyl, 2-butoxyethyl or 2-phenoxyethyl), a cycloalkyl group having 5 to 24 (preferably 6 to 18) carbon atoms (for example, cyclopentyl, cyclohexyl, 4-t-butylcyclohexyl or 4-methylcyclohexyl), or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, phenyl, cresyl, p-nonylphenyl, xylyl, cumenyl, p-methoxyphenyl or p-methoxycarbonylphenyl).
In the formula [S-2], each of R4 and R5 represents an alkyl group having 1 to 24 (preferably 4 to 18) carbon atoms (for example, alkyl mentioned above as being represented by R1, ethoxycarbonylmethyl, 1,1-diethylpropyl, 2-ethyl-1-methylhexyl, cyclohexylmethyl or 1-ethyl-1,5-dimethylhexyl), a cycloalkyl group having 5 to 24 (preferably 6 to 18) carbon atoms (for example, cycloalkyl mentioned above as being represented by R1, 3,3,5-trimethylcyclohexyl, mentyl, bornyl or 1-methylcyclohexyl), or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, aryl mentioned above as being represented by R1, 4-t-butylphenyl, 4-t-octylphenyl, 1,3,5-trimethylphenyl, 2,4-di-t-butylphenyl or 2,4-di-t-pentylphenyl). R6 represents a halogen atom (preferably Cl), an alkyl group having 1 to 18 carbon atoms (for example, methyl, isopropyl, t-butyl or n-dodecyl), an alkoxy group having 1 to 18 carbon atoms (for example, methoxy, n-butoxy, n-octyloxy, methoxyethoxy or benzyloxy), an aryloxy group having 6 to 18 carbon atoms (for example, phenoxy, p-tolyloxy, 4-methoxyphenoxy or 4-t-butylphenoxy) or an alkoxycarbonyl group having 2 to 19 carbon atoms (for example, methoxycaronyl, n-butoxycaronyl or 2-ethylhexyloxycaronyl); and a is 0 to 3 (preferably 0 or 1).
In the formula [S-3], Ar represents an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, phenyl, 4-chlorophenyl, 4-methoxyphenyl, 1-naphthyl, 4-n-butoxyphenyl or 1,3,5-trimethylphenyl), and b is an integer of 1 to 6 (preferably 1 to 3). R7 represents a b-valent hydrocarbon group having 2 to 24 (preferably 2 to 18) carbon atoms [for example, alkyl, cycloalkyl or aryl mentioned above as being represented by R4, xe2x80x94(CH2)2xe2x80x94, 
or a b-valent group of hydrocarbons coupled with each other through an ether bond having 4 to 24 (preferably 4 to 18) carbon atoms [for example, xe2x80x94CH2CH2OCH2CH2xe2x80x94, xe2x80x94CH2CH2(OCH2CH2)3xe2x80x94, xe2x80x94CH2CH2CH2OCH2CH2CH2xe2x80x94, 
In the formula [S-4], R8 represents an alkyl group having 1 to 24 (preferably 1 to 17) carbon atoms (for example, methyl, n-propyl, 1-hydroxyethyl, 1-ethylpentyl, n-undecyl, pentadecyl or 8,9-epoxyheptadecyl) or a cycloalkyl group having 3 to 24 (preferably 6 to 18) carbon atoms (for example, cyclopropyl, cyclohexyl or 4-methylcyclohexyl); and c is an integer of 1 to 6 (preferably 1 to 3). R9 represents a c-valent hydrocarbon group having 2 to 24 (preferably 2 to 18) carbon atoms or a c-valent group of hydrocarbons coupled with each other through an ether bond having 4 to 24 (preferably 4 to 18) carbon atoms (for example, group mentioned above as being represented by R7).
In the formula [S-5], d is 2 to 6 (preferably 2 or 3); and R10 represents a d-valent hydrocarbon group [for example, 
R11 represents an alkyl group having 1 to 24 (preferably 4 to 18) carbon atoms, a cycloalkyl group having 5 to 24 (preferably 6 to 18) carbon atoms or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms [for example, alkyl, cycloalkyl or aryl mentioned above as being represented by R4].
In the formula [S-6], R12 represents an alkyl group having 1 to 24 (preferably 3 to 20) carbon atoms [for example, n-propyl, 1-ethylpentyl, n-undecyl, n-pentadecyl, 2,4-di-t-pentylphenoxymethyl, 4-t-octylphenoxymethyl, 3-(2,4-di-t-butylphenoxy)propyl or 1-(2,4-di-t-butylphenoxy)propyl], a cycloalkyl group having 5 to 24 (preferably 6 to 18) carbon atoms (for example, cyclohexyl or 4-methylcyclohexyl) or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, aryl mentioned above as being represented by Ar). Each of R13 and R14 represents an alkyl group having 1 to 24 (preferably 1 to 18) carbon atoms (for example, methyl, ethyl, isopropyl, n-butyl, n-hexyl, 2-ethylhexyl or n-dodecyl), a cycloalkyl group having 3 to 18 (preferably 3 to 15) carbon atoms (for example, cyclopentyl or cyclopropyl) or an aryl group having 6 to 18 (preferably 6 to 15) carbon atoms (for example, phenyl, 1-naphthyl or p-tolyl). R13 and R14 may be bonded with each other to thereby form a pyrrolidine ring, a piperidine ring or a morpholine ring in cooperation with N. R12 and R13 may be bonded with each other to thereby form a pyrrolidone ring.
In the formula [S-7], R15 represents an alkyl group having 1 to 24 (preferably 1 to 18) carbon atoms (for example, methyl, isopropyl, t-butyl, t-pentyl, t-hexyl, t-octyl, 2-butyl, 2-hexyl, 2-octyl, 2-dodecyl, 2-hexadecyl or t-pentadecyl), a cycloalkyl group having 3 to 18 (preferably 5 to 12) carbon atoms (for example, cyclopentyl or cyclohexyl), an alkoxycarbonyl group having 2 to 24 (preferably 5 to 17) carbon atoms (for example, n-butoxycarbonyl, 2-ethylhexyloxycarbonyl or n-dodecyloxycarbonyl), an alkylsulfonyl group having 1 to 24 (preferably 1 to 18) carbon atoms (for example, methylsulfonyl, n-butylsulfonyl or n-dodecylsulfonyl), an arylsulfonyl group having 6 to 30 (preferably 6 to 24) carbon atoms (for example, p-tolylsulfonyl, p-dodecylphenylsulfonyl or p-hexadecyloxyphenylsulfonyl), an aryl group having 6 to 32 (preferably 6 to 24) carbon atoms (for example, phenyl or p-tolyl) or a cyano group. R16 represents a halogen atom (preferably Cl), an alkyl group having 1 to 24 (preferably 1 to 18) carbon atoms (for example, alkyl mentioned above as being represented by R15), a cycloalkyl group having 3 to 18 (preferably 5 to 17) carbon atoms (for example, cyclopentyl or cyclohexyl), an aryl group having 6 to 32 (preferably 6 to 24) carbon atoms (for example, phenyl or p-tolyl), an alkoxy group having 1 to 24 (preferably 1 to 18) carbon atoms (for example, methoxy, n-butoxy, 2-ethylhexyloxy, benzyloxy, n-dodecyloxy or n-hexadecyloxy) or an aryloxy group having 6 to 32 (preferably 6 to 24) carbon atoms (for example, phenoxy, p-t-butylphenoxy, p-t-octylphenoxy, m-pentadecylphenoxy or p-dodecyloxyphenoxy); and e is an integer of 0 to 3 (preferably 1 or 2).
In the formula [S-8], R17 and R18 have the same meaning as those of the above R13 and R14. R19 has the same meaning as that of the above R16; and f is an integer of 0 to 4 (preferably 0 to 2).
Among the high-boiling organic solvents represented by the formulae [S-1] to [S-8], those represented by the formula [S-1] (R1, R2 and R3 are preferably alkyl groups), [S-2], [S-3] (b is preferably 1), [S-4], [S-5] and [S-7] are preferred. The high-boiling organic solvents represented by the formulae [S-1], [S-2], [S-4] and [S-5] are most preferred. Specific examples of the high-boiling organic solvents for use in the present invention will be set out below:
These high-boiling organic solvents may be used individually or in mixture [for example, mixtures of di(2-ethylhexyl) phthalate and trioctyl phosphate, di(2-ethylhexyl) sebacate and triisononyl phosphate, and dibutyl phthalate and di(2-ethylhexyl) adipate]. When two or more high-boiling organic solvents are used in combination, it is preferred that the dielectric constant of the mixture be 7.0 or less.
Other compound examples of the high-boiling organic solvents for use in the present invention and/or processes for synthesizing such high-boiling organic solvents are described in, for example, U.S. Pat. Nos. 2,322,027, 2,533,514, 2,772,163, 2,835,579, 3,594,171, 3,676,137, 3,689,271, 3,700,454, 3,748,141, 3,764,336, 3,765,897, 3,912,515, 3,936,303, 4,004,929, 4,080,209, 4,127,413, 4,193,802, 4,207,393, 4,220,711, 4,239,851, 4,278,757, 4,353,979, 4,363,873, 4,430,421, 4,464,464, 4,483,918, 4,540,657, 4,684,606, 4,728,599 and 4,745,049, EP Nos. 276,319A, 286,253A, 289,820A, 309,158A, 309,159A and 309,160A, JP-A""s-48-47335, 50-26530, 51-25133, 51-26036, 51-277921, 51-27922, 51-149028, 52-46816, 53-1520, 53-1521, 53-15127, 53-146622, 54-106228, 56-64333, 56-81836, 59-204041, 61-84641, 62-118345, 62-247364, 63-167357, 63-214744, 63-301941 and 64-68745, and Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-) 1-101543 and JP-A-1-102454.
In the present invention, the high-boiling organic solvent is preferably contained as an emulsified substance (microdispersion). The average particle diameter of emulsified substance is preferably 50 xcexcm or less, more preferably 10 xcexcm or less, still more preferably 2 xcexcm or less, and most preferably 0.5 xcexcm or less. In the preparation of emulsified substance, although a dispersion can be effected only by mechanical agitation, it is preferred to add a surfactant. Further, the emulsified substance is preferably prepared by adding a polymer such as gelatin thereto.
The content of high-boiling organic solvent in the emulsion is preferably in the range of 0.05 to 10%, more preferably 0.1 to 10%, and most preferably 0.2 to 10% on a mass basis (mass of high-boiling organic solvent contained in 100 g of emulsion).
In the present invention, the expression xe2x80x9cwhen the emulsion of the present invention is agitated at 40xc2x0 C. for 30 min, the variation of absorption spectrum ranging from 400 nm to 700 nm thereof is within 10%xe2x80x9d means that, in the entire range from 400 nm to 700 nm, the difference between the absorbance before emulsion agitation and that after emulsion agitation is within 10%, or that the difference between the absorbance at absorption maximum before emulsion agitation and that after emulsion agitation or the difference between the absorption integrated intensity ranging from 400 nm to 700 nm before emulsion agitation and that after emulsion agitation is within 10%.
In the present invention, the expression xe2x80x9cwhen the silver halide photographic lightsensitive material is aged at 60xc2x0 C. in 30% humidity for 3 days, the variation of absorption spectrum ranging from 400 nm to 700 nm is within 10%xe2x80x9d means that, in the entire range from 400 nm to 700 nm, the difference between the absorbance before aging of the silver halide photographic emulsion layer and that after aging of the silver halide photographic emulsion layer is within 10%, or that the difference between the absorbance at absorption maximum before aging of the silver halide photographic emulsion layer and that after aging of the silver halide photographic emulsion layer or the difference between the absorption integrated intensity ranging from 400 nm to 700 nm before aging of the silver halide photographic emulsion layer and that after aging of the silver halide photographic emulsion layer is within 10%.
The compound being reactive with developing agent oxidation products, which can be employed in the present invention, is a yellow dye forming coupler represented by the above formula 1 wherein R1 represents a tertiary alkyl group or an aryl group; R2 represents a hydrogen atom, a halogen atom (F, Cl, Br or I; hereinafter, the same applies in the illustration of the formula 1), an alkoxy group, an aryloxy group, an alkyl group or a dialkylamino group; R3 represents a group capable of effecting a substitution on a benzene ring; x represents a hydrogen atom or a heterocycle capable of being eliminated by a coupling reaction with an oxidation product of aromatic primary amine developing agent and capable of bonding at a nitrogen atom with a coupling active site; and L is an integer of 0 to 4, provided that, when L is two or more, two or more R3 groups may be identical with or different from each other.
R3 is, for example, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, a carbonamido group, a sulfonamido group, a carbamoyl group, a sulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, a ureido group, a sulfamoylamino group, an alkoxycarbonylamino group, a nitro group, a heterocyclic group, a cyano group, an acyl group, an acyloxy group, an alkylsulfonyloxy group or an arylsulfonyloxy group. When R1 is a tertiary alkyl group, it may contain a cyclic structure such as cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.
In the formula 1, it is preferred that R1 represent a t-butyl group, a 1-methylcyclopropyl group, a phenyl group, or a phenyl group substituted with a halogen atom, an alkyl group or an alkoxy group; R2 represent a halogen atom, an alkoxy group or a phenoxy group; R3 represent a halogen atom, an alkoxy group, an alkoxycarbonyl group, a carbonamido group, a sulfonamido group, a carbamoyl group or a sulfamoyl group; X represent a 5 to 7-membered heterocyclic group capable of bonding at a nitrogen atom with a coupling active site, which may contain N, S, O or P; and L be an integer of 0 to 2.
The coupler represented by the formula 1 may be a dimer, higher polymer, homopolymer or copolymer containing noncoupling polymer units, which can bond through a divalent group or group of higher valence at substituent R1, X or 
Specific examples of the couplers of the formula 1 will be set out below: 
Other compound examples of the yellow couplers for use in the present invention and/or processes for synthesizing such yellow couplers are described in, for example, U.S. Pat. Nos. 3,227,554, 3,408,194, 3,894,875, 3,933,501, 3,973,968, 4,022,620, 4,057,432, 4,115,121, 4,203,768, 4,248,961, 4,266,019, 4,314,023, 4,327,175, 4,401,752, 4,404,274, 4,420,556, 4,711,837 and 4,729,944, EP Nos. 30,747A, 284,081A, 296,793A and 313,308A, DE No. 3,107,173C, and JP-A""s-58-42044, 59-174839, 62-276547 and 63-123047.
The first preferable method for realizing silver halide grains of less than 500 nm spectral absorption maximum wavelength and 60 or more light absorption intensity, or 500 nm or more spectral absorption maximum wavelength and 100 or more light absorption intensity, is any of those using the following specified dyes.
For example, there can preferably be employed the method of using a dye having an aromatic group, or using cationic and anionic dyes having aromatic groups in combination as described in JP-A""s 10-239789, 8-269009, 10-123650 and 8-328189; the method of using a dye of polyvalent charge as described in JP-A-10-171058; the method of using a dye having a pyridinium group as described in JP-A-10-104774; the method of using a dye having a hydrophobic group as described in JP-A-10-186559; the method of using a dye having a coordination bond group as described in JP-A-10-197980; and the method of using specified dyes as described in JP-A""s 2000-256573, 2000-275776, 2000-345061, 2000-345060, 2001-005132, 2001-075220, 2001-092068, 2001-081341, 2001-152038, 2001-152044, 2001-075221, 2001-152037, 2001-166413 and Japanese Patent Application No. 2000-18966.
The method of using a dye having at least one aromatic group is most preferred. In particular, the method wherein a positively charged dye, or a dye having intra-molecularly offset charges, or a dye having no charges is used alone, and the method wherein positively and negatively charged dyes are used in combination, at least one thereof having at least one aromatic group as a substituent, are preferred.
The aromatic group will now be described in detail. The aromatic group may be a hydrocarbon aromatic group or a heteroaromatic group. Further, the aromatic group may be a group having the structure of a polycyclic condensed ring resulting from mutual condensation of hydrocarbon aromatic rings or heteroaromatic rings, or a polycyclic condensed ring consisting of a combination of an aromatic hydrocarbon ring and an aromatic heterocycle. The aromatic group may be substituted with, for example, substituent V described later. Examples of preferred aromatic rings contained in the aromatic group include benzene, naphthalene, anthracene, phenanthrene, fluorene, triphenylene, naphthacene, biphenyl, pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, indole, benzofuran, benzothiophene, isobenzofuran, quinolizine, quinoline, phthalazine, naphthyridine, quinoxaline, quinoxazoline, quinoline, carbazole, phenanthridine, acridine, phenanthroline, thianthrene, chromene, xanthene, phenoxathiin, phenothiazine and phenazine.
The above hydrocarbon aromatic rings are more preferred. Benzene and naphthalene are most preferred. Benzene is optimal.
For example, any of those aforementioned as examples of dye chromophores can be used as the dye. The dyes aforementioned as examples of polymethine dye chromophores can preferably be employed.
More preferred are a cyanine dye, a styryl dye, a hemicyanine dye, a merocyanine dye, a trinuclear merocyanine dye, a tetranuclear merocyanine dye, a rhodacyanine dye, a complex cyanine dye, a complex merocyanine dye, an allopolar dye, an oxonol dye, a hemioxonol dye, a squarium dye, a croconium dye and an azamethine dye. Still more preferred are a cyanine dye, a merocyanine dye, a trinuclear merocyanine dye, a tetranuclear merocyanine dye and a rhodacyanine dye. Most preferred are a cyanine dye, a merocyanine dye and a rhodacyanine dye. A cyanine dye is optimal.
Especially preferred methods will be described in detail below with reference to shown structural formulae.
Specifically, the following methods (1) and (2) are preferred. Of them, the method (2) is more preferred.
(1) In this method, use is made of at least one member of cationic, betaine and nonionic methine dyes represented by the following general formula (I).
(2) In this method, at least one member of cationic methine dyes represented by the following general formula (I) and at least one member of anionic methine dyes represented by the following general formula (II) are simultaneously used. 
In this formula, Z1 represents an atomic group needed to form a nitrogenous heterocycle, provided that a ring condensation may have been effected thereto. R1 represents an alkyl group, an aryl group or a heterocyclic group. Q1 represents a group needed for the compound of the general formula (I) to form a methine dye. Each of L1 and L2 represents a methine group, and p1 is 0 or 1.
Provided, however, that Z1, R1, Q1, L1 and L2 should have such substituents that the methine dye of the general formula (I) as a whole constitutes a cationic dye, a betaine dye or a nonionic dye. Provided that, when the general formula (I) represents a cyanine dye or a rhodacyanine dye, they preferably have such substituents that the methine dye as a whole constitutes a cationic dye. M1 represents a counter ion for charge balance, and m1 is a number of 0 or greater needed to neutralize a molecular charge. 
In this formula, Z2 represents an atomic group needed to form a nitrogenous heterocycle, provided that a ring condensation may have been effected thereto. R2 represents an alkyl group, an aryl group or a heterocyclic group. Q2 represents a group needed for the compound of the general formula (II) to form a methine dye. Each of L3 and L4 represents a methine group, and p2 is 0 or 1.
Provided, however, that Z2, R2, Q2, L3 and L4 should have such substituents that the methine dye of the general formula (II) as a whole constitutes an anionic dye. M2 represents a counter ion for charge balance, and m2 is a number of 0 or greater needed to neutralize a molecular charge.
When the compound of the general formula (I) is employed alone, it is preferred that R1 be a group having an aromatic ring.
When the compound of the general formula (I) is employed in combination with the compound of the general formula (II), it is preferred that at least one of R1 and R2 be a group having an aromatic ring.
More preferably, R1 and R2 simultaneously represent a group having an aromatic ring.
Although the cationic dye for use in the present invention is not particularly limited as long as the charges of dye exclusive of counter ions are cationic, it is preferred that the cationic dye be a dye having no anionic substituents. Further, although the anionic dye for use in the present invention is not particularly limited as long as the charges of dye exclusive of counter ions are anionic, it is preferred that the anionic dye be a dye having at least one anionic substituent. The betaine dye for use in the present invention is a dye which, although having charges in its molecule, forms such an intramolecular salt that the molecule as a whole has no charges. The nonionic dye for use in the present invention is a dye having no charges at all in its molecule.
Herein, the anionic substituent refers to a substituent having a negative charge, and can be, for example, a proton dissociative acid group, at least 90% of which undergoes dissociation at a pH of 5 to 8. Examples of suitable anionic substituents include a sulfo group, a carboxyl group, a sulfato group, a phosphate group and a borate group. As other examples of anionic substituents, there can be mentioned groups from which proton is dissociated depending on the pKa thereof and the environmental pH, such as xe2x80x94CONHSO2xe2x80x94 (sulfonylcarbamoyl group or carbonylsulfamoyl group), xe2x80x94CONHCOxe2x80x94 (carbonylcarbamoyl group), xe2x80x94SO2NHSO2xe2x80x94 (sulfonylsulfamoyl group) and phenolic hydroxyl. Of these, a sulfo group, a carboxyl group, xe2x80x94CONHSO2xe2x80x94, xe2x80x94CONHCOxe2x80x94 and xe2x80x94SO2NHSO2xe2x80x94 are preferred.
The groups of the formulae xe2x80x94CONHSO2xe2x80x94, xe2x80x94CONHCOxe2x80x94 and xe2x80x94SO2NHSO2xe2x80x94 may not dissociate proton depending on the pKa thereof and the environmental pH. In such instances, the groups are not included in the anionic substituents mentioned herein. That is, when any proton dissociation does not occur, for example, the dye represented by the general formula (I-1) given below, even if substituted with two of such groups, can be regarded as cationic dye.
As the cationic substituent, there can be mentioned, for example, substituted or unsubstituted ammonium groups and pyridinium groups.
Among the dyes of the general formula (I), those of the following general formulae (I-1), (I-2) and (I-3) are especially preferred. 
In the general formula (I-1), each of L5, L6, L7, L8, L9, L10 and L11 represents a methine group, each of p3 and p4 is 0 or 1, and n1 is 0, 1, 2, 3 or 4. Each of Z3 and Z4 represents an atomic group needed to form a nitrogenous heterocycle, provided that a ring condensation may have been effected thereto. Each of R3 and R4 represents an alkyl group, an aryl group or a heterocyclic group. M1 and m1 have the same meaning as in the general formula (I). Provided that R3, R4, Z3, Z4 and L5 to L11 have no anionic substituent when the general formula (I-1) represents a cationic dye and have one anionic substituent when the general formula (I-1) represents a betaine dye. 
In the general formula (I-2), each of L12, L13, L14 and L15 represents a methine group, p5 is 0 or 1, q1 is 0 or 1, and n2 is 0, 1, 2, 3 or 4. Z5 represents an atomic group needed to form a nitrogenous heterocycle, and Z6 and Z6xe2x80x2 represent atomic groups needed to form a heterocycle or a noncyclic acid terminal in cooperation with (Nxe2x80x94R6)q1, provided that a ring condensation may have been effected to Z5 and Z6 and Z6xe2x80x2. Each of R5 and R6 represents an alkyl group, an aryl group or a heterocyclic group. M1 and m1 have the same meaning as in the general formula (I). Provided that R5, R6, Z5, Z6 and L12 to L15 have a cationic substituent when the general formula (I-2) represents a cationic dye, have one cationic substituent together with one anionic substituent when the general formula (I-2) represents a betaine dye, and have no cationic substituent and no anionic substituent when the general formula (I-2) represents a nonionic dye. 
In the general formula (I-3), each of L16, L17, L18, L19, L20, L21, L22, L23 and L24 represents a methine group, each of p6 and p7 is 0 or 1, q2 is 0 or 1, and each of n3 and n4 is 0, 1, 2, 3 or 4. Each of Z7 and Z9 represents an atomic group needed to form a nitrogenous heterocycle, and Z8 and Z8xe2x80x2 represent atomic groups needed to form a heterocycle in cooperation with (Nxe2x80x94R8)q2, provided that a ring condensation may have been effected to Z7, Z8 and Z8xe2x80x2, and Z9. Each of R7, R8 and R9 represents an alkyl group, an aryl group or a heterocyclic group. M1 and m1 have the same meaning as in the general formula (I). Provided that R7, R8, R9, Z7, Z8, Z9 and L16 to L24 have no anionic substituent when the general formula (I-3) represents a cationic dye and have one anionic substituent when the general formula (I-3) represents a betaine dye.
Among the anionic dyes of the general formula (II), those of the following general formulae (II-1), (II-2) and (II-3) are especially preferred. 
In the general formula (II-1), each of L25, L26, L27, L28, L29, L30 and L31 represents a methine group, each of p8 and p9 is 0 or 1, and n5 is 0, 1, 2, 3 or 4. Each of Z10 and Z11 represents an atomic group needed to form a nitrogenous heterocycle, provided that a ring condensation may have been effected thereto. Each of R10 and R11 represents an alkyl group, an aryl group or a heterocyclic group. M2 and m2 have the same meaning as in the general formula (II). Provided that R10 and R11 have an anionic substituent. 
In the general formula (II-2), each of L32, L33, L34 and L35 represents a methine group, p9 is 0 or 1, q3 is 0 or 1, and n6 is 0, 1, 2, 3 or 4. Z12 represents an atomic group needed to form a nitrogenous heterocycle, and Z13 and Z13xe2x80x2 represent atomic groups needed to form a heterocycle or a noncyclic acid terminal in cooperation with (Nxe2x80x94R13)q3, provided that a ring condensation may have been effected to Z12 and Z13 and Z13xe2x80x2. Each of R12 and R13 represents an alkyl group, an aryl group or a heterocyclic group. M2 and m2 have the same meaning as in the general formula (II). Provided that at least one of R12 and R13 has an anionic substituent. 
In the general formula (II-3), each of L36, L37, L38, L39, L40, L41, L42, L43 and L44 represents a methine group, each of p10 and p11 is 0 or 1, q4 is 0 or 1, and each of n7 and n8 is 0, 1, 2, 3 or 4. Each of Z14 and Z16 represents an atomic group needed to form a nitrogenous heterocycle, and Z15 and Z15xe2x80x2 represent atomic groups needed to form a heterocycle in cooperation with (Nxe2x80x94R15)q4, provided that a ring condensation may have been effected to Z14, Z15 and Z15xe2x80x2, and Z16. Each of R14, R15 and R16 represents an alkyl group, an aryl group or a heterocyclic group. M2 and m2 have the same meaning as in the general formula (II). Provided that at least two of R14, R15 and R16 have an anionic substituent.
When the compounds of the general formulae (I-1), (I-2) and (I-3) are used alone, at least one, preferably both, of R3 and R4 represents a group having an aromatic ring; at least one, preferably both, of R5 and R6 represents a group having an aromatic ring; and at least one, preferably at least two, and more preferably all three, of R7, R8 and R9 represents a group having an aromatic ring.
When the compounds of the general formulae (I-1), (I-2) and (I-3) are used in combination with the compounds of the general formulae (II-1), (II-2) and (II-3), at least one, preferably two, more preferably three, and most preferably four or more, of R3 to R9 and R10 to R16 of the combined dyes represents a group having an aromatic ring.
Although silver halide grains of less than 500 nm spectral absorption maximum wavelength and 60 or more light absorption intensity, or 500 nm or more spectral absorption maximum wavelength and 100 or more light absorption intensity, can be realized by the above preferred method, the dye of the second layer is generally adsorbed in the form of a monomer, so that most often the absorption width and spectral sensitivity width are larger than those desired. Therefore, for realizing a high sensitivity within a desired wavelength region, it is preferred that the dye adsorbed into the second layer form a J-association product. Further, the J-association product is preferred from the viewpoint of transmitting light energy absorbed by the dye of the second layer to the dye of the first layer with a proximate light absorption wavelength by the energy transfer of the Forster type, because of the high fluorescent yield and slight Stokes shift exhibited thereby.
In the present invention, the dye of the second et seq. layers refers to the dye that is adsorbed on silver halide grains, the adsorption being, however, not directly effected on the silver halide grains.
In the present invention, the J-association of the dye of the second et seq. layers is defined as the large-wavelength-side absorption width of absorption exhibited by the dye adsorbed in the second et seq. layers being not greater than twice the large-wavelength-side absorption width of absorption exhibited by a dye solution in monomeric form wherein there is no interaction between dye chromophores. Herein, the large-wavelength-side absorption width refers to the energy width between absorption maximum wavelength and such wavelength that is larger than the absorption maximum wavelength and exhibits absorption equal to xc2xd of absorption maximum. It is generally known that, upon the formation of J-association product, the large-wavelength-side absorption width becomes small as compared with that in monomeric form. When the dye is adsorbed in monomeric form into the second layer, there results nonuniformity of adsorption position and form to thereby bring about an increase to two or more times the large-wavelength-side absorption width of absorption exhibited by a dye solution in monomeric form. Therefore, the above definition enables defining the J-association product of the dye of the second et seq. layers.
The spectral absorption of the dye adsorbed into the second et seq. layers can be determined by subtracting the spectral absorption attributed to the dye of the first layer from the total spectral absorption of the emulsion.
The spectral absorption attributed to the dye of the first layer can be determined by measuring the absorption spectrum exhibited when only the first-layer dye has been added. Further, the spectrum of spectral absorption attributed to the dye of the first layer can be measured by adding a dye desorbing agent to the emulsion having sensitizing dyes adsorbed in multilayer form to thereby desorb the dye of the second et seq. layers.
In an experiment of desorbing dyes from grain surface with the use of a dye desorbing agent, generally, the dye of the first layer is removed only after the desorption of the dye of the second et seq. layers. Therefore, the spectral absorption attributed to the dye of the first layer can be determined by selecting appropriate desorption conditions. As a result, the spectral absorption of the dye of the second et seq. layers can be determined. With respect to the method of using a dye desorbing agent, reference can be made to report of Asanuma (Journal of Physical Chemistry B, vol. 101, pages 2149 to 2153 (1997)).
For forming the J-association product of the dye of the second layer from a cationic dye, betaine dye, or nonionic dye represented by the general formula (I) or an anionic dye represented by the general formula (II), it is preferred that the addition of dye adsorbed as the first layer be separated from the addition of dye adsorbed in the formation of the second et seq. layers, and it is more preferred that the structure of the dye of the first layer be different from that of the dye of the second et seq. layers. With respect to the dye of the second et seq. layers, it is preferred that a cationic dye, a betaine dye and a nonionic dye be added individually, or a cationic dye and an anionic dye be added in combination.
The dye of the first layer, although not particularly limited, preferably consists of the dye represented by the general formula (I) or the general formula (II), more preferably represented by the general formula (I).
As the second-layer dye, the cationic dye, betaine dye or nonionic dye represented by the general formula (I) is preferably used alone. When a cationic dye and an anionic dye are used in combination as an also preferred second-layer dye, it is preferred that one of them be the cationic dye of the general formula (I) or the anionic dye of the general formula (II). More preferably, both the cationic dye of the general formula (I) and the anionic dye of the general formula (II) are contained in the second layer. The ratio of cationic dye to anionic dye in the dye of the second layer is preferably in the range of 0.5 to 2, more preferably 0.75 to 1.33, and most preferably 0.9 to 1.11.
In the present invention, although dyes other than those represented by the general formula (I) and the general formula (II) can be added, the dyes of the general formula (I) or the general formula (II) are preferably added in an amount of 50% or more, more preferably 70% or more, and most preferably 90% or more, based on the total addition amount of dyes.
The addition of second-layer dyes in the above manner enables increasing the interaction between second-layer dyes while promoting a rearrangement of second-layer dyes, so that the formation of J-association product can be realized.
With respect to the dyes of the general formula (I) or the general formula (II), when used as the first-layer dye, it is preferred that each of Z1 and Z2 be a basic nucleus substituted with an aromatic group or a basic nucleus resulting from condensation of three or more rings. In the use as the dye of the second et seq. layer, it is preferred that each of Z1 and Z2 be a basic nucleus resulting from condensation of three or more rings.
With respect to the number of condensed rings in basic nuclei, it is, for example, 2 in a benzoxazole nucleus and 3 in a naphthoxazole nucleus. Even if the benzoxazole nucleus is substituted with a phenyl group, the number of condensed rings thereof is 2. Although the basic nucleus resulting from condensation of three or more rings is not particularly limited as long as it is a polycyclic condensed-ring-type heterocyclic basic nucleus resulting from condensation of three or more rings, it is preferred that the basic nucleus consist of a tricyclic condensed-ring-type heterocycle or a tetracyclic condensed-ring-type heterocycle. As a preferred tricyclic condensed-ring-type heterocycle, there can be mentioned, for example, naphth[2,3-d]oxazole, naphth[1,2-d]oxazole, naphth[2,1-d]oxazole, naphtho[2,3-d]thiazole, naphtho[1,2-d]thiazole, naphtho[2,1-d]thiazole, naphth[2,3-d]imidazole, naphth[1,2-d]imidazole, naphth[2,1-d]imidazole, naphtho[2,3-d]selenazole, naphtho[1,2-d]selenazole, naphtho[2,1-d]selenazole, indol[5,6-d]oxazole, indol[6,5-d]oxazole, indol[2,3-d]oxazole, indolo[5,6-d]thiazole, indolo[6,5-d]thiazole, indolo[2,3-d]thiazole, benzofur[5,6-d]oxazole, benzofur[6,5-d]oxazole, benzofur[2,3-d]oxazole, benzofuro[5,6-d]thiazole, benzofuro[6,5-d]thiazole, benzofuro[2,3-d]thiazole, benzothien[5,6-d]oxazole, benzothien[6,5-d]oxazole or benzothien[2,3-d]oxazole. As a preferred tetracyclic condensed-ring-type heterocycle, there can be mentioned, for example, anthr[2,3-d]oxazole, anthr[1,2-d]oxazole, anthr[2,1-d]oxazole, anthra[2,3-d]thiazole, anthra[1,2-d]thiazole, phenanthro[2,1-d]thiazole, phenanthr[2,3-d]imidazole, anthr[1,2-d]imidazole, anthr[2,1-d]imidazole, anthra[2,3-d]selenazole, phenanthro[1,2-d]selenazole, phenanthro[2,1-d]selenazole, carbazol[2,3-d]oxazole, carbazol[3,2-d]oxazole, dibenzofur[2,3-d]oxazole, dibenzofur[3,2-d]oxazole, carbazolo[2,3-d]thiazole, carbazolo[3,2-d]thiazole, dibenzofuro[2,3-d]thiazole, dibenzofuro[3,2-d]thiazole, benzofur[5,6-d]oxazole, dibenzothien[2,3-d]oxazole, dibenzothien[3,2-d]oxazole, tetrahydrocarbazol[6,7-d]oxazole, tetrahydrocarbazol[7,6-d]oxazole, dibenzothieno[2,3-d]thiazole, dibenzothieno[3,2-d]thiazole or tetrahydrocarbazolo[6,7-d]thiazole. The basic nucleus resulting from condensation of three or more rings is more preferably selected from among naphth[2,3-d]oxazole, naphth[1,2-d]oxazole, naphth[2,1-d]oxazole, naphtho[2,3-d]thiazole, naphtho[1,2-d]thiazole, naphtho[2,1-d]thiazole, indol[5,6-d]oxazole, indol[6,5-d]oxazole, indol[2,3-d]oxazole, indolo[5,6-d]thiazole, indolo[2,3-d]thiazole, benzofur[5,6-d]oxazole, benzofur[6,5-d]oxazole, benzofur[2,3-d]oxazole, benzofuro[5,6-d]thiazole, benzofuro[2,3-d]thiazole, benzothien[5,6-d]oxazole, anthr[2,3-d]oxazole, anthr[1,2-d]oxazole, anthra[2,3-d]thiazole, anthra[1,2-d]thiazole, carbazol[2,3-d]oxazole, carbazol[3,2-d]oxazole, dibenzofur[2,3-d]oxazole, dibenzofur[3,2-d]oxazole, carbazolo[2,3-d]thiazole, carbazolo[3,2-d]thiazole, dibenzofuro[2,3-d]thiazole, dibenzofuro[3,2-d]thiazole, dibenzothien[2,3-d]oxazole and dibenzothien[3,2-d]oxazole. The basic nucleus resulting from condensation of three or more rings is most preferably selected from among naphth[2,3-d]oxazole, naphth[1,2-d]oxazole, naphtho[2,3-d]thiazole, indol[5,6-d]oxazole, indol[6,5-d]oxazole, indolo[5,6-d]thiazole, benzofur[5,6-d]oxazole, benzofuro[5,6-d]thiazole, benzofuro[2,3-d]thiazole, benzothien[5,6-d]oxazole, carbazol[2,3-d]oxazole, carbazol[3,2-d]oxazole, dibenzofur[2,3-d]oxazole, dibenzofur[3,2-d]oxazole, carbazolo[2,3-d]thiazole, carbazolo[3,2-d]thiazole, dibenzofuro[2,3-d]thiazole, dibenzofuro[3,2-d]thiazole, dibenzothien[2,3-d]oxazole and dibenzothien[3,2-d]oxazole.
Another preferable method for realizing such a state of adsorption that the surface of silver halide grains is coated with a multilayer of dye chromophores comprises utilizing a dye compound having two or more dye chromophore portions connected to each other by a covalent bond through a connecting group. Usable dye chromophores are not particularly limited, and, for example, the aforementioned dye chromophores can be employed. The aforementioned polymethine dye chromophores are preferred. More preferred are a cyanine dye, a merocyanine dye, a rhodacyanine dye and an oxonol dye. Most preferred are a cyanine dye, a rhodacyanine dye and a merocyanine dye. A cyanine dye is optimal.
Preferred examples thereof include the method of using dyes connected to each other by methine chains as described in JP-A-9-265144, the method of using a dye comprising oxonol dyes connected to each other as described in JP-A-10-226758, the method of using connected dyes of specified structure as described in JP-A""s-10-110107, 10-307358, 10-307359 and 10-310715, the method of using connected dyes having specified connecting groups as described in JP-A""s-9-265143 and 10-204306, the method of using connected dyes of specified structure as described in JP-A""s-2000-231174, 2000-231172 and 2000-231173, and the method of using a dye having a reactive group to thereby form a connected dye in the emulsion as described in JP-A-2000-081678.
As preferred connected dyes, there can be mentioned those of the following general formula (III).
D1-(La-[D2]q)rxe2x80x83xe2x80x83III
M3m3
In the formula, each of D1 and D2 represents a dye chromophore. La represents a connecting group or a single bond, and each of q and r is an integer of 1 to 100. M3 represents a charge balance counter ion, and m3 is a number required to neutralize a molecular charge.
D1, D2 and La will be described in greater detail.
The dye chromophore represented by D1 or D2 is not particularly limited, and, for example, the aforementioned dye chromophores can be employed. The aforementioned polymethine dye chromophores are preferred. More preferred are a cyanine dye, a merocyanine dye, a rhodacyanine dye and an oxonol dye. Most preferred are a cyanine dye, a merocyanine dye and a rhodacyanine dye. A cyanine dye is optimal.
As preferred general formulae for dyes, there can be mentioned those given on pages 32 to 36 of U.S. Pat. No. 5,994,051 and on pages 30 to 34 of U.S. Pat. No. 5,747,236. As preferred general formulae for cyanine dyes, merocyanine dyes and rhodacyanine dyes, there can be mentioned those given on columns 21 and 22 of U.S. Pat. No. 5,340,694 ((XI), (XII) and (XIII) wherein n12, n15, n17 and n18 are numbers not particularly limited, for example, an integer of 0 or greater (preferably 4 or less)).
In the present invention, when the connected dye of the general formula (III) is adsorbed on silver halide grains, it is preferred that D2 be a chromophore not directly adsorbed on silver halides.
That is, it is preferred that the adsorptive force of D2 to silver halide grains be smaller than that of D1. Further, it is most preferred that the adsorptive force to silver halide grains be in the order of D1 greater than La greater than D2.
Although, as aforementioned, D1 is preferably a sensitizing dye moiety having adsorptivity to silver halide grains, the adsorption thereof can equally be effected by a physical adsorption or a chemical adsorption.
Preferably, D2 exhibits low adsorptivity to silver halide grains and consists of a luminescent dye. With respect to the type of luminescent dye, those having the skeletal structure of dye for use in dye laser are preferred. These are pigeonholed in, for example, Mitsuo Maeda, Laser Kenkyu (Laser Research), vol. 8, pp. 694, 803 and 958 (1980) and ibid, vol. 9, page 85 (1981), and F. Sehaefer, xe2x80x9cDye Lasersxe2x80x9d, Springer (1973).
Moreover, it is preferred that the absorption maximum wavelength of D1 in the silver halide photographic lightsensitive material be greater than that of D2. Further, preferably, the light emission of D2 and the absorption of D1 overlap each other. Also, it is preferred that D1 form a J-association product. Still further, for enabling the connected dye of the general formula (III) to exhibit absorption and spectral sensitivity within desired wavelength ranges, it is preferred that D2 also form a J-association product.
Although the reduction potentials and oxidation potentials of D1 and D2 are not limited, it is preferred that the reduction potential of D1 be noble to the value of reduction potential of D2 minus 0.2V.
La represents a connecting group (preferably a divalent connecting group) or a single bond. This connecting group preferably consists of an atom or atomic group including at least one member selected from among a carbon atom, a nitrogen atom, a sulfur atom and an oxygen atom. Also, the connecting group is preferably one having 0 to 100 carbon atoms, more preferably 1 to 20 carbon atoms, constituted of one member or a combination of at least two members selected from among an alkylene group (e.g., methylene, ethylene, propylene, butylene or pentylene), an arylene group (e.g., phenylene or naphthylene), an alkenylene group (e.g., ethenylene or propenylene), an alkynylene group (e.g., ethynylene or propynylene), an amido group, an ester group, a sulfoamido group, a sulfonic ester group, a ureido group, a sulfonyl group, a sulfinyl group, a thioether group, an ether group, a carbonyl group, xe2x80x94N(Va)xe2x80x94 (Va represents a hydrogen atom or a monovalent substituent; as the monovalent substituent, there can be mentioned V described later) and a heterocyclic bivalent group (e.g., 6-chloro-1,3,5-triazine-2,4-diyl group, pyrimidine-2,4-diyl group or quinoxarine-2,3-diyl group).
The above connecting group may further have a substituent represented by V described later, and may contain a ring (aromatic or nonaromatic hydrocarbon ring or heterocycle).
As more preferred connecting groups, there can be mentioned alkylene groups each having 1 to 10 carbon atoms (e.g., methylene, ethylene, propylene and butylene), arylene groups each having 6 to 10 carbon atoms (e.g., phenylene and naphthylene), alkenylene groups each having 2 to 10 carbon atoms (e.g., ethenylene and propenylene), alkynylene groups each having 2 to 10 carbon atoms (e.g., ethynylene and propynylene), and bivalent substituents each comprising one member or a combination of two or more members selected from among an ether group, an amido group, an ester group, a sulfoamido group and a sulfonic ester group and having 1 to 10 carbon atoms. These may be substituted with V described later.
La is a connecting group which may induce an energy transfer or electron moving by through-bond interaction. The through-bond interaction includes, for example, tunnel interaction and super-exchange interaction. Especially, the through-bond interaction based on super-exchange interaction is preferred. The through-bond interaction and super-exchange interaction are as defined in Shammai Speiser, Chem. Rev., vol. 96, pp. 1960-1963, 1996. As the connecting group capable of inducing an energy transfer or electron moving by such an interaction, there can preferably be employed those described in Shammai Speiser, Chem. Rev., vol. 96, pp. 1967-1969, 1996.
Each of q and r is an integer of 1 to 100, preferably 1 to 5, more preferably 1 or 2, and most preferably 1. When q and r are 2 or greater, the contained plurality of La""s and D2""s may represent connecting groups and dye chromophores which are different from each other, respectively.
The dyes of the general formula (III) preferably have a charge of xe2x88x921 as a whole.
More preferably, in the general formula (III), each of D1 and D2 independently represents a methine dye represented by the following general formula (IV), (V), (VI) or (VII). 
In the general formula (IV), each of L45, L46, L47, L48, L49, L50 and L51 represents a methine group, each of p12 and p13 is 0 or 1, and n9 is 0, 1, 2, 3 or 4. Each of Z17 and Z18 represents an atomic group needed to form a nitrogenous heterocycle, provided that a ring condensation may have been effected thereto. M4 represents a charge balance counter ion, and m4 is a number of 0 or greater required to neutralize a molecular charge. Each of R17 and R18 represents an alkyl group, an aryl group or a heterocyclic group. 
In the general formula (V), each of L52, L53, L54 and L55 represents a methine group, p14 is 0 or 1, q5 is 0 or 1, and n10 is 0, 1, 2, 3 or 4. Z19 represents an atomic group needed to form a nitrogenous heterocycle, and Z20 and Z20xe2x80x2 represent atomic groups needed to form a heterocycle or a noncyclic acid terminal in cooperation with (Nxe2x80x94R20)q5, provided that a ring condensation may have been effected to Z19 and Z20 and Z20xe2x80x2. M5 represents a charge balance counter ion, and m5 is a number of 0 or greater required to neutralize a molecular charge. Each of R19 and R20 represents an alkyl group, an aryl group or a heterocyclic group. 
In the general formula (VI), each of L56, L57, L58, L59, L60, L61, L62, L63 and L64 represents a methine group, each of p15 and p16 is 0 or 1, q6 is 0 or 1, and each of n11 and n12 is 0, 1, 2, 3 or 4. Each of Z21 and Z23 represents an atomic group needed to form a nitrogenous heterocycle, and Z22 and Z22xe2x80x2 represent atomic groups needed to form a heterocycle in cooperation with (Nxe2x80x94R22)q6, provided that a ring condensation may have been effected to Z21, Z22 and Z22xe2x80x2, and Z23. M6 represents a charge balance counter ion, and m6 is a number of 0 or greater required to neutralize a molecular charge. Each of R21, R22 and R23 represents an alkyl group, an aryl group or a heterocyclic group. 
In the general formula (VII), each of L65, L66 and L67 represents a methine group, each of q7 and q8 is 0 or 1, and n13 is 0, 1, 2, 3 or 4. Z24 and Z24xe2x80x2, and Z25 and Z25xe2x80x2, represent atomic groups needed to form a heterocycle or a noncyclic acid terminal in cooperation with (Nxe2x80x94R24)q7 and (Nxe2x80x94R25)q8, respectively, provided that a ring condensation may have been effected to Z24 and Z24xe2x80x2, and Z25 and Z25xe2x80x2. M7 represents a charge balance counter ion, and m7 is a number of 0 or greater required to neutralize a molecular charge. Each of R24 and R25 represents an alkyl group, an aryl group or a heterocyclic group.
D1 of the general formula (III) preferably represents a methine dye of the above general formula (IV), (V) or (VI), more preferably a methine dye of the general formula (IV). D2 of the general formula (III) preferably represents a methine dye of the above general formula (IV), (V) or (VII), more preferably a methine dye of the general formula (IV) or (V), and most preferably a methine dye of the general formula (IV).
The methine compounds represented by the general formulae (I) (including formulae I-1,2,3), (II) (including formulae II-1,2,3), (IV), (V), (VI) and (VII) will be described in detail below.
In the general formulae (I) and (II), each of Q1 and Q2 represents a group needed to form a methine dye. As methine dyes, although any type thereof can be formed by selecting Q1 and Q2, there can be mentioned those set out hereinbefore as examples of dye chromophores.
As preferred methine dyes, there can be mentioned, for example, a cyanine dye, a merocyanine dye, a rhodacyanine dye, a trinuclear merocyanine dye, a tetranuclear merocyanine dye, an allopolar dye, a hemicyanine dye and a styryl dye. As more preferred methine dyes, there can be mentioned a cyanine dye, a merocyanine dye and a rhodacyanine dye. A cyanine dye is most preferred. Details of these dyes are described in, for example, F. M. Harmer, xe2x80x9cHeterocyclic Compounds-Cyanine Dyes and Related Compoundsxe2x80x9d, John Wiley and Sons, New York, London, 1964 and D. M. Sturmer, xe2x80x9cHeterocyclic Compounds-Special topics in heterocyclic chemistryxe2x80x9d, chapter 18, section 14, pages 482 to 515.
As general formulae for preferred dyes, there can be mentioned those given on pages 32 to 36 of U.S. Pat. No. 5,994,051 and those given on pages 30 to 34 of U.S. Pat. No. 5,747,236. As general formulae for preferred cyanine dye, merocyanine dye and rhodacyanine dye, there can be mentioned those given in U.S. Pat. No. 5,340,694, columns 21 to 22, (XI), (XII) and (XIII) (wherein the numbers n12, n15, n17 and n18 are not limited, for example, an integer of 0 or greater (preferably 4 or less)).
With respect to the general formulae (I) and (II), when a cyanine dye or a rhodacyanine dye is formed by Q1 and Q2, they can be expressed by the following resonance formulae. 
In the general formulae (I), (II), (IV), (V) and (VI), each of Z1, Z2, Z3, Z4, Z5, Z7, Z9, Z10, Z11, Z12, Z14, Z16, Z17, Z18, Z19, Z21 and Z23 represents an atomic group needed to form a nitrogenous heterocycle, preferably a 5 or 6-membered nitrogenous heterocycle, provided that a ring condensation may have been effected thereto. The ring may be an aromatic or a nonaromatic ring, preferably an aromatic ring. For example, it can be a hydrocarbon aromatic ring such as a benzene ring or a naphthalene ring, or a heteroaromatic ring such as a pyrazine ring or a thiophene ring.
The nitrogenous heterocycle can be, for example, any of a thiazoline nucleus, a thiazole nucleus, a benzothiazole nucleus, an oxazoline nucleus, an oxazole nucleus, a benzoxazole nucleus, a selenazoline nucleus, a selenazole nucleus, a benzoselenazole nucleus, a 3,3-dialkylindolenine nucleus (e.g., 3,3-dimethylindolenine), an imidazoline nucleus, an imidazole nucleus, a benzimidazole nucleus, a 2-pyridine nucleus, a 4-pyridine nucleus, a 2-quinoline nucleus, a 4-quinoline nucleus, a 1-isoquinoline nucleus, a 3-isoquinoline nucleus, an imidazo[4,5-b]quinoxaline nucleus, an oxadiazole nucleus, a thiadiazole nucleus, a tetrazole nucleus and a pyrimidine nucleus. Of these, a benzothiazole nucleus, a benzoxazole nucleus, a 3,3-dialkylindolenine nucleus (e.g., 3,3-dimethylindolenine), a benzimidazole nucleus, a 2-pyridine nucleus, a 4-pyridine nucleus, a 2-quinoline nucleus, a 4-quinoline nucleus, a 1-isoquinoline nucleus and a 3-isoquinoline nucleus are preferred. A benzothiazole nucleus, a benzoxazole nucleus, a 3,3-dialkylindolenine nucleus (e.g., 3,3-dimethylindolenine) and a benzimidazole nucleus are more preferred. A benzoxazole nucleus, a benzothiazole nucleus and a benzimidazole nucleus are still more preferred. A benzoxazole nucleus and a benzothiazole nucleus are most preferred.
These nitrogenous heterocycle may have a substituent represented by V. The substituent represented by V, although not particularly limited, can be, for example, a halogen atom, an alkyl group (including a cycloalkyl and a bicycloalkyl), an alkenyl group (including a cycloalkenyl and a bicycloalkenyl), an alkynyl group, an aryl group, a heterocyclic group, a cyano group, a hydroxyl group, a nitro group, a carboxyl group, an alkoxy group, an aryloxy group, a silyloxy group, a heterocyclic oxy group, an acyloxy group, a carbamoyloxy group, an alkoxycarbonyloxy group, an aryloxycarbonyloxy group, an amino group (including anilino), an acylamino group, an aminocarbonylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamino group, a sulfamoylamino group, an alkyl- or arylsulfonylamino group, a mercapto group, an alkylthio group, an arylthio group, a heterocyclic thio group, a sulfamoyl group, a sulfo group, an alkyl- or arylsulfinyl group, an alkyl- or arylsulfonyl group, an acyl group, an aryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, an aryl- or heterocyclic azo group, an imido group, a phosphino group, a phosphinyl group, a phosphinyloxy group, a phosphinylamino group, or a silyl group.
More specifically, the substituent represented by V can be a halogen atom (e.g., a chlorine atom, a bromine atom or an iodine atom); an alkyl group [representing a linear, branched or cyclic substituted or unsubstituted alkyl group, and including an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl or 2-ethylhexyl), a cycloalkyl group (preferably a substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms, such as cyclohexyl, cyclopentyl or 4-n-dodecylcyclohexyl), a bicycloalkyl group (preferably a substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms, which is a monovalent group corresponding to a bicycloalkane having 5 to 30 carbon atoms from which one hydrogen atom is removed, such as bicyclo[1,2,2]heptan-2-yl or bicyclo[2,2,2]octan-3-yl), and a tricyclo or more cycle structure; the alkyl contained in the following substituents (for example, alkyl of alkylthio group) also means the alkyl group of this concept]; an alkenyl group [representing a linear, branched or cyclic substituted or unsubstituted alkenyl group, and including an alkenyl group (preferably a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, such as vinyl, allyl, pulenyl, geranyl or oleyl), a cycloalkenyl group (preferably a substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms, which is a monovalent group corresponding to a cycloalkene having 3 to 30 carbon atoms from which one hydrogen atom is removed, such as 2-cyclopenten-1-yl or 2-cyclohexen-1-yl), and a bicycloalkenyl group (substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms, which is a monovalent group corresponding to a bicycloalkene having one double bond from which one hydrogen atom is removed, such as bicyclo[2,2,1]hept-2-en-1-yl or bicyclo[2,2,2]oct-2-en-4-yl)]; an alkynyl group (preferably a substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms, such as ethynyl, propargyl or trimethylsilylethynyl); an aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as phenyl, p-tolyl, naphthyl, m-chlorophenyl or o-hexadecanoylaminophenyl); a heterocyclic group (preferably a monovalent group corresponding to a 5- or 6-membered substituted or unsubstituted aromatic or nonaromatic heterocyclic compound from which one hydrogen atom is removed, more preferably a 5- or 6-membered aromatic heterocyclic group having 3 to 30 carbon atoms, such as 2-furyl, 2-thienyl, 2-pyrimidinyl or 2-benzothiazolyl); a cyano group; a hydroxyl group; a nitro group; a carboxyl group; an alkoxy group (preferably a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms, such as methoxy, ethoxy, isopropoxy, t-butoxy, n-octyloxy or 2-methoxyethoxy); an aryloxy group (preferably a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, such as phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy or 2-tetradecanoylaminophenoxy); a silyloxy group (preferably a silyloxy group having 3 to 20 carbon atoms, such as trimethylsilyloxy or t-butyldimethylsilyloxy); a heterocyclic oxy group (preferably a substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms, such as 1-phenyltetrazol-5-oxy or 2-tetrahydropyranyloxy); an acyloxy group (preferably a formyloxy group, a substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms or a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms, such as formyloxy, acetyloxy, pivaloyloxy, stearoyloxy, benzoyloxy or n-methoxyphenylcarbonyloxy); a carbamoyloxy group (preferably a substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms, such as N,N-dimethylcarbamoyloxy, N,N-diethylcarbamoyloxy, morpholinocarbonyloxy, N,N-di-n-octylaminocarbonyloxy or N-n-octylcarbamoyloxy); an alkoxycarbonyloxy group (preferably a substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms, such as methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy or n-octylcarbonyloxy); an aryloxycarbonyloxy group (preferably a substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms, such as phenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy or p-n-hexadecyloxyphenoxycarbonyloxy); an amino group (preferably an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms or a substituted or unsubstituted anilino group having 6 to 30 carbon atoms, such as amino, methylamino, dimethylamino, anilino, N-methylanilino or diphenylamino); an acylamino group (preferably an formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms or a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms, such as formylamino, acetylamino, pivaloylamino, lauroylamino, benzoylamino or 3,4,5-tri-n-octyloxyphenylcarbonylamino); an aminocarbonylamino group (preferably a substituted or unsubstituted aminocarbonylamino group having 1 to 30 carbon atoms, such as carbamoylamino, N,N-dimethylaminocarbonylamino, N,N-diethylaminocarbonylamino or morpholinocarbonylamino); an alkoxycarbonylamino group (preferably a substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms, such as methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino or N-methyl-methoxycarbonylamino); an aryloxycarbonylamino group (preferably a substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms, such as phenoxycarbonylamino, p-chlorophenoxycarbonylamino or m-n-octyloxyphenoxycarbonylamino); a sulfamoylamino group (preferably a substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms, such as sulfamoylamino, N,N-dimethylaminosulfonylamino or N-n-octylaminosulfonylamino); an alkyl- or arylsulfonylamino group (preferably a substituted or unsubstituted alkylsulfonylamino group having 1 to 30 carbon atoms or a substituted or unsubstituted arylsulfonylamino group having 6 to 30 carbon atoms, such as methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino or p-methylphenylsulfonylamino); a mercapto group; an alkylthio group (preferably a substituted or unsubstituted alkylthio group having 1 to 30 carbon atoms, such as methylthio, ethylthio or n-hexadecylthio); an arylthio group (preferably a substituted or unsubstituted arylthio group having 6 to 30 carbon atoms, such as phenylthio, p-chlorophenylthio or m-methoxyphenylthio); a heterocyclic thio group (preferably a substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms, such as 2-benzothiazolylthio or 1-phenyltetrazol-5-ylthio); a sulfamoyl group (preferably a substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms, such as N-ethylsulfamoyl, N-(3-dodecyloxypropyl)sulfamoyl, N,N-dimethylsulfamoyl, N-acetylsulfamoyl, N-benzoylsulfamoyl or N-(Nxe2x80x2-phenylcarbamoyl)sulfamoyl); a sulfo group; an alkyl- or arylsulfinyl group (preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms or a substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms, such as methylsulfinyl, ethylsulfinyl, phenylsulfinyl or p-methylphenylsulfinyl); an alkyl- or arylsulfonyl group (preferably a substituted or unsubstituted alkylsulfonyl group having 1 to 30 carbon atoms or a substituted or unsubstituted arylsulfonyl group having 6 to 30 carbon atoms, such as methylsulfonyl, ethylsulfonyl, phenylsulfonyl or p-methylphenylsulfonyl); an acyl group (preferably a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms or a substituted or unsubstituted heterocyclic carbonyl group having 4 to 30 carbon atoms wherein a carbonyl group is bonded at carbon atom, such as acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, p-n-octyloxyphenylcarbonyl, 2-pyridylcarbonyl or 2-furylcarbonyl); an aryloxycarbonyl group (preferably a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms, such as phenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl or p-t-butylphenoxycarbonyl); an alkoxycarbonyl group (preferably a substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl or n-octadecyloxycarbonyl); a carbamoyl group (preferably a substituted or unsubstituted carbamoyl group having 1 to 30 carbon atoms, such as carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N,N-di-n-octylcarbamoyl or N-(methylsulfonyl)carbamoyl); an aryl- or heterocyclic azo group (preferably a substituted or unsubstituted arylazo group having 6 to 30 carbon atoms or a substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms, such as phenylazo, p-chlorophenylazo or 5-ethylthio-1,3,4-thiadiazol-2-ylazo); an imido group (preferably N-succinimido or N-phthalimido); a phosphino group (preferably a substituted or unsubstituted phosphino group having 2 to 30 carbon atoms, such as dimethylphosphino, diphenylphosphino or methylphenoxyphosphino); a phosphinyl group (preferably a substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms, such as phosphinyl, dioctyloxyphosphinyl or diethoxyphosphinyl); a phosphinyloxy group (preferably a substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms, such as diphenoxyphosphinyloxy or dioctyloxyphosphinyloxy); a phosphinylamino group (preferably a substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms, such as dimethoxyphosphinylamino or dimethylaminophosphinylamino); or a silyl group (preferably a substituted or unsubstituted silyl group having 3 to 30 carbon atoms, such as trimethylsilyl, t-butyldimethylsilyl or phenyldimethylsilyl).
The substituent represented by V can have the structure of a condensate of rings (including aromatic and nonaromatic hydrocarbon rings and heterocycles, and further including polycyclic condensed rings resulting from combination thereof; for example, a benzene ring, a naphthalene ring, an anthracene ring, a quinoline ring, a phenanthrene ring, a fluorene ring, a triphenylene ring, a naphthacene ring, a biphenyl ring, a pyrrole ring, a furan ring, a thiophene ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, an indolizine ring, an indole ring, a benzofuran ring, a benzothiophene ring, an isobenzofuran ring, a quinolizine ring, a quinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinoxazoline ring, a quinoline ring, a carbazole ring, a phenanthridine ring, an acridine ring, a phenanthroline ring, a thianthrene ring, a chromene ring, a xanthene ring, a phenoxathiin ring, a phenothiazine ring and a phenazine ring).
With respect to those having a hydrogen atom among the above-listed functional groups, the hydrogen atom may be replaced by any of the above-listed groups. Examples of such functional groups include an alkylcarbonylaminosulfonyl group, an arylcarbonylaminosulfonyl group, an alkylsulfonylaminocarbonyl group and an arylsulfonylaminocarbonyl group. Specific examples thereof include methylsulfonylaminocarbonyl, p-methylphenylsulfonylaminocarbonyl, acetylaminosulfonyl and benzoylaminosulfonyl groups.
As preferred substituents, there can be mentioned the above-listed alkyl group, aryl group, alkoxy group, halogen atom, aromatic ring condensate, sulfo group, carboxyl group and hydroxy group.
The substituent V on Z1, Z2, Z3, Z4, Z5, Z7, Z9, Z10, Z11, Z12, Z14 and Z16 is more preferably an aromatic group or an aromatic ring condensate.
When the methine dye of the general formula (IV), (V) or (VI) represents the chromophore represented by D1 of the general formula (III), the substituent V on Z17, Z18, Z19, Z21 and Z23 is more preferably an aromatic group or an aromatic ring condensate.
When the methine dye of the general formula (IV), (V) or (VI) represents the chromophore represented by D2 of the general formula (III), the substituent V on Z17, Z18, Z19, Z21 and Z23 is more preferably a carboxy group, a sulfo group or a hydroxy group, and most preferably a sulfo group.
Each of combinations of Z6 and Z6xe2x80x2 with (Nxe2x80x94R6)q1, Z13 and Z13xe2x80x2 with (Nxe2x80x94R13)q3, Z20 and Z20xe2x80x2 with (Nxe2x80x94R20)q5, Z24 and Z24xe2x80x2 with (Nxe2x80x94R24)q7, and Z25 and Z25xe2x80x2 with (Nxe2x80x94R25)q8 represent atomic groups needed to form a heterocycle or a noncyclic acid terminal. The heterocycle (preferably 5 or 6-membered heterocycle), although not limited, is preferably an acid nucleus. Below, the acid nucleus and noncyclic acid terminal will be described. The acid nucleus and noncyclic acid terminal can have the form of any common acid nucleus and noncyclic acid terminal of merocyanine dye. In preferred form, each of Z6, Z13, Z20, Z24 and Z25 represents a thiocarbonyl group, a carbonyl group, an ester group, an acyl group, a carbamoyl group, a cyano group or a sulfonyl group, and more preferably represents a thiocarbonyl group or a carbonyl group. Each of Z6xe2x80x2, Z13xe2x80x2, Z20 xe2x80x2 and Z24 xe2x80x2 represents a remaining moiety of atomic group needed to form the acid nucleus and noncyclic acid terminal. In the formation of a noncyclic acid terminal, it is preferred that, for example, a thiocarbonyl group, a carbonyl group, an ester group, an acyl group, a carbamoyl group, a cyano group or a sulfonyl group be represented thereby.
Each of q1, q3, q5, q7 and q8 is 0 or 1, preferably 1.
The acid nucleus and noncyclic acid terminal mentioned herein are described on, for example, pages 198 to 200 of T. H. James, The Theory of the Photographic Process, 4th ed., Macmillan, 1977. Herein, the noncyclic acid terminal refers to an acid, namely, electron acceptant terminal which does not form any ring. Particulars of the acid nucleus and noncyclic acid terminal are described in, for example, U.S. Pat. Nos. 3,567,719, 3,575,869, 3,804,634, 3,837,862, 4,002,480 and 4,925,777, JP-A-3-167546, and U.S. Pat. Nos. 5,994,051 and 5,747,236.
The acid nucleus is preferred when a heterocycle (preferably a 5 or 6-membered nitrogenous heterocycle) consisting of carbon, nitrogen and/or chalcogen (typically, oxygen, sulfur, selenium and tellurium) atoms is formed, and is more preferred when a 5 or 6-membered nitrogenous heterocycle consisting of carbon, nitrogen and/or chalcogen (typically, oxygen, sulfur, selenium and tellurium) atoms is formed. For example, there can be mentioned the following acid nuclei:
2-pyrazolin-5-one, pyrazolidine-3,5-dione, imidazolin-5-one, hydantoin, 2 or 4-thiohydantoin, 2-iminoxazolidin-4-one, 2-oxazolin-5-one, 2-thioxazolidine-2,5-dione, 2-thioxazoline-2,4-dione, isoxazolin-5-one, 2-thiazolin-4-one, thiazolidin-4-one, thiazolidine-2,4-dione, rhodanine, thiazolidine-2,4-dithione, isorhodanine, indane-1,3-dione, thiophen-3-one, thiophen-3-one-1,1-dioxide, indolin-2-one, indolin-3-one, 2-oxoindazolinium, 3-oxoindazolinium, 5,7-dioxo-6,7-dihydrothiazolo[3,2-a]pyrimidine, cyclohexane-1,3-dione, 3,4-dihydroisoquinolin-4-one, 1,3-dioxane-4,6-dione, barbituric acid, 2-thiobarbituric acid, chroman-2,4-dione, indazolin-2-one, pyrido[1,2-a]pyrimidine-1,3-dione, pyrazolo[1,5-b]quinazolone, pyrazolo[1,5-a]benzimidazole, pyrazolopyridone, 1,2,3,4-tetrahydroquinoline-2,4-dione, 3-oxo-2,3-dihydrobenzo[d]thiophene-1,1-dioxide, and 3-dicyanomethine-2,3-dihydrobenzo[d]thiophene-1,1-dioxide nuclei; and
nuclei having an exomethylene structure resulting from substitution of a carbonyl group or thiocarbonyl group as a constituent of these nuclei at an active methylene site of acid nucleus, and nuclei having an exomethylene structure resulting from substitution at an active methylene site of active methylene compound having the structure of, for example, a cyanomethylene or ketomethylene as a feedstock of noncyclic acid terminal.
Ring condensation or substitution by rings or substituents listed above with respect to the substituent V may be effected to these acid nuclei and noncyclic acid terminals.
As preferred combinations of Z6 and Z6xe2x80x2 with (Nxe2x80x94R6)q1, Z13 and Z13xe2x80x2 with (Nxe2x80x94R13)q3, Z20 and Z20xe2x80x2 with (Nxe2x80x94R20)q5, Z24 and Z24xe2x80x2 with (Nxe2x80x94R24)q7, and Z25 and Z25xe2x80x2 with (Nxe2x80x94R25)q8, there can be mentioned hydantoin, 2 or 4-thiohydantoin, 2-oxazolin-5-one, 2-thioxazoline-2,4-dione, thiazolidine-2,4-dione, rhodanine, thiazolidine-2,4-dithione, barbituric acid and 2-thiobarbituric acid. As more preferred combinations, there can be mentioned hydantoin, 2 or 4-thiohydantoin, 2-oxazolin-5-one, rhodanine, barbituric acid and 2-thiobarbituric acid. As most preferred combinations, there can be mentioned 2 or 4-thiohydantoin, 2-oxazolin-5-one, rhodanine and barbituric acid.
Heterocycles formed by combinations of Z8 and Z8xe2x80x2 with (Nxe2x80x94R8)q2, Z15 and Z15xe2x80x2 with (Nxe2x80x94R15)q4 and Z22 and Z22xe2x80x2 with (Nxe2x80x94R22)q6 can be the same as listed above as the heterocycles by combinations of Z6 and Z6xe2x80x2 with (Nxe2x80x94R6)q1, Z13 and Z13xe2x80x2 with (Nxe2x80x94R13)q3, Z20 and Z20xe2x80x2 with (Nxe2x80x94R20)q5, Z24 and Z24xe2x80x2 with (Nxe2x80x94R24)q7, and Z25 and Z25xe2x80x2 with (Nxe2x80x94R25)q8. As preferred heterocycles, there can be mentioned those obtained by removing an oxo group or a thioxo group from the acid nuclei listed above with respect to the heterocycles by combinations of Z6 and Z6xe2x80x2 with (Nxe2x80x94R6)q1, Z13 and Z13xe2x80x2 with (Nxe2x80x94R13)q3, Z20 and Z20xe2x80x2 with (Nxe2x80x94R20)q5, Z24 and Z24xe2x80x2 with (Nxe2x80x94R24)q7, and Z25 and Z25xe2x80x2 with (Nxe2x80x94R25)q8.
As more preferred heterocycles, there can be mentioned those obtained by removing an oxo group or a thioxo group from the acid nuclei listed above as specific examples of combinations of Z6 and Z6xe2x80x2 with (Nxe2x80x94R6)q1, Z13 and Z13xe2x80x2 with (Nxe2x80x94R13)q3, Z20 and Z20xe2x80x2 with (Nxe2x80x94R20)q5, Z24 and Z24xe2x80x2 with (Nxe2x80x94R24)q7, and Z25 and Z25xe2x80x2 with (Nxe2x80x94R25)q8.
As still more preferred heterocycles, there can be mentioned those obtained by removing an oxo group or a thioxo group from hydantoin, 2 or 4-thiohydantoin, 2_oxazolin-5-one, 2-thioxazoline-2,4-dione, thiazolidine-2,4-dione, rhodanine, thiazolidine-2,4-dithione, barbituric acid and 2-thiobarbituric acid. As yet still more preferred heterocycles, there can be mentioned those obtained by removing an oxo group or a thioxo group from hydantoin, 2 or 4-thiohydantoin, 2-oxazolin-5-one, rhodanine, barbituric acid and 2-thiobarbituric acid. As most preferred heterocycles, there can be mentioned those obtained by removing an oxo group or a thioxo group from 2 or 4-thiohydantoin, 2-oxazolin-5-one and rhodanine.
Each of q2, q4 and q6 is 0 or 1, preferably 1.
Each of R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23, R24 and R25 represents an alkyl group, an aryl group or a heterocyclic group. Specifically, each represents, for example, an unsubstituted alkyl group having 1 to 18, preferably 1 to 7, and more preferably 1 to 4 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, hexyl, octyl, dodecyl or octadecyl); a substituted alkyl group having 1 to 18, preferably 1 to 7, and more preferably 1 to 4 carbon atoms {for example, an alkyl group substituted with the above substituent V, preferably an aralkyl group (e.g., benzyl or 2-phenylethyl), an unsaturated hydrocarbon group (e.g., allyl), a hydroxyalkyl group (e.g., 2-hydroxyethyl or 3-hydroxypropyl), a carboxyalkyl group (e.g., 2-carboxyethyl, 3-carboxypropyl, 4-carboxybutyl or carboxymethyl), an alkoxyalkyl group (e.g., 2-methoxyethyl or 2-(2-methoxyethoxy)ethyl), an aryloxyalkyl group (e.g., 2-phenoxyethyl or 2-(1-naphthoxy)ethyl), an alkoxycarbonylalkyl group (e.g., ethoxycarbonylmethyl or 2-benzyloxycarbonylethyl), an aryloxycarbonylalkyl group (e.g., 3-phenoxycarbonylpropyl), an acyloxyalkyl group (e.g., 2-acetyloxyethyl), an acylalkyl group (e.g., 2-acetylethyl), a carbamoylalkyl group (e.g., 2-morpholinocarbonylethyl), a sulfamoylalkyl group (e.g., N,N-dimethylsulfamoylmethyl), a sulfoalkyl group (e.g., 2-sulfoethyl, 3-sulfopropyl, 3-sulfobutyl, 4-sulfobutyl, 2-[3-sulfopropoxy]ethyl, 2-hydroxy-3-sulfopropyl or 3-sulfopropoxyethoxyethyl), a sulfoalkenyl group, a sulfatoalkyl group (e.g., 2-sulfatoethyl, 3-sulfatopropyl or 4-sulfatobutyl), a heterocycle-substituted alkyl group (e.g., 2-(pyrrolidin-2-on-1-yl)ethyl or tetrahydrofurfuryl), an alkylsulfonylcarbamoylalkyl group (e.g., methanesulfonylcarbamoylmethyl), an acylcarbamoylalkyl group (e.g., acetylcarbamoylmethyl), an acylsulfamoylalkyl group (e.g., acetylsulfamoylmethyl), or an alkylsulfonylsulfamoylalkyl group (e.g., methanesulfonylsulfamoylmethyl)}; an unsubstituted aryl group having 6 to 20, preferably 6 to 10, and more preferably 6 to 8 carbon atoms (e.g., phenyl or 1-naphthyl); a substituted aryl group having 6 to 20, preferably 6 to 10, and more preferably 6 to 8 carbon atoms (for example, an aryl group substituted with the above V mentioned as substituent examples, such as p-mehtoxyphenyl, p-methylphenyl or p-chlorophenyl); an unsubstituted heterocyclic group having 1 to 20, preferably 3 to 10, and more preferably 4 to 8 carbon atoms (e.g., 2-furyl, 2-thienyl, 2-pyridyl, 3-pyrazolyl, 3-isoxazolyl, 3-isothiazolyl, 2-imidazolyl, 3-oxazolyl, 2-thiazolyl, 2-pyridazyl, 2-pyrimidyl, 3-pyrazyl, 2-(1,3,5-triazolyl), 3-(1,2,4-triazolyl) or 5-tetrazolyl); or a substituted heterocyclic group having 1 to 20, preferably 3 to 10, and more preferably 4 to 8 carbon atoms (for example, a heterocyclic group substituted with the above V mentioned as substituent examples, such as 5-methyl-2-thienyl or 4-methoxy-2-pyridyl).
Each of R1, R3, R4, R5, R6, R7, R8 and R9 preferably represents a group having an aromatic ring. The aromatic ring can be a hydrocarbon aromatic ring or a heteroaromatic ring, which, further, may be a polycyclic condensed ring resulting from mutual condensation of hydrocarbon aromatic rings or heteroaromatic rings, or a polycyclic condensed ring consisting of a combination of an aromatic hydrocarbon ring and an aromatic heterocycle. The aromatic ring may be substituted with the above-listed substituent V. As preferred aromatic rings, there can be mentioned those listed as aromatic ring examples in the above description of aromatic groups.
The group having an aromatic ring can be represented by the formula xe2x80x94Lbxe2x80x94A1xe2x80x94, wherein Lb represents a single bond or a connecting group. A1 represents an aromatic group. As preferred Lb connecting groups, there can be mentioned those described above as being represented by La. As preferred A1 aromatic groups, there can be mentioned those listed above as aromatic group examples.
Preferably, as an alkyl group having a hydrocarbon aromatic ring, there can be mentioned, for example, an aralkyl group (e.g., benzyl, 2-phenylethyl, naphthylmethyl or 2-(4-biphenyl)ethyl), an aryloxyalkyl group (e.g., 2-phenoxyethyl, 2-(1-naphthoxy)ethyl, 2-(4-biphenyloxy)ethyl, 2-(o, m or p-halophenoxy)ethyl or 2-(o, m or p-methoxyphenoxy)ethyl)), or an aryloxycarbonylalkyl group (3-phenoxycarbonylpropyl or 2-(1-naphthoxycarbonyl)ethyl). Further, as an alkyl group having a heteroaromatic ring, there can be mentioned, for example, 2-(2-pyridyl)ethyl, 2-(4-pyridyl)ethyl, 2-(2-furyl)ethyl, 2-(2-thienyl)ethyl or 2-(2-pyridylmethoxy)ethyl. The hydrocarbon aromatic group can be, for example, 4-methoxyphenyl, phenyl, naphthyl or biphenyl. The heteroaromatic group can be, for example, 2-thienyl, 4-chloro-2-thienyl, 2-pyridyl or 3-pyrazolyl.
More preferably, the group having an aromatic ring is the above alkyl group having a substituted or unsubstituted hydrocarbon aromatic ring or heteroaromatic ring. Most preferably, the group having an aromatic ring is the above alkyl group having a substituted or unsubstituted hydrocarbon aromatic ring.
Each of R2, R10, R11, R12, R13, R14, R15 and R16 preferably represents a group having an aromatic ring. Both of R10 and R11, at least one of R12 and R13, and at least one of R14, R15 and R16, has an anionic substituent. R2 preferably has an anionic substituent. The aromatic ring can be a hydrocarbon aromatic ring or a heteroaromatic ring, which, further, may be a polycyclic condensed ring resulting from mutual condensation of hydrocarbon aromatic rings or heteroaromatic rings, or a polycyclic condensed ring consisting of a combination of an aromatic hydrocarbon ring and an aromatic heterocycle. The aromatic ring may be substituted with the above-listed substituent V. As preferred aromatic rings, there can be mentioned those listed as aromatic ring examples in the above description of aromatic groups.
The group having an aromatic ring can be represented by the formula xe2x80x94Lcxe2x80x94A2xe2x80x94, wherein Lc represents a single bond or a connecting group. A2 represents an aromatic group. As preferred Lc connecting groups, there can be mentioned those described above as being represented by La. As preferred A2 aromatic groups, there can be mentioned those listed above as aromatic group examples. Lc or A2 is preferably substituted with at least one anionic substituent.
Preferably, as an alkyl group having a hydrocarbon aromatic ring, there can be mentioned, for example, an aralkyl group substituted with a sulfo group, a phosphate group and/or a carboxyl group (e.g., 2-sulfobenzyl, 4-sulfobenzyl, 4-sulfophenethyl, 3-phenyl-3-sulfopropyl, 3-phenyl-2-sulfopropyl, 4,4-diphenyl-3-sulfobutyl, 2-(4xe2x80x2-sulfo-4-biphenyl)ethyl or 4-phosphobenzyl); an aryloxycarbonylalkyl group substituted with a sulfo group, a phosphato group and/or a carboxyl group (e.g., 3-sulfophenoxycarbonylpropyl); or an aryloxyalkyl group substituted with a sulfo group, a phosphato group and/or a carboxyl group (e.g., 2-(4-sulfophenoxy)ethyl, 2-(2-phosphophenoxy)ethyl or 4,4-diphenoxy-3-sulfobutyl).
Further, as an alkyl group having a heteroaromatic ring, there can be mentioned, for example, 3-(2-pyridyl)-3-sulfopropyl, 3-(2-furyl)-3-sulfopropyl or 2-(2-thienyl)-2-sulfopropyl.
As a hydrocarbon aromatic group, there can be mentioned, for example, an aryl group substituted with a sulfo group, a phosphato group and/or a carboxyl group (e.g., 4-sulfophenyl or 4-sulfonaphthyl). As a heteroaromatic group, there can be mentioned, for example, a heterocyclic group substituted with a sulfo group, a phosphato group and/or a carboxyl group (e.g., 4-sulfo-2-thienyl or 4-sulfo-2-pyridyl).
More preferably, the group having an aromatic ring is the above alkyl group having a heteroaromatic ring or hydrocarbon aromatic ring substituted with a sulfo group, a phosphato group and/or a carboxyl group. Still more preferably, the group having an aromatic ring is the above alkyl group having a hydrocarbon aromatic ring substituted with a sulfo group, a phosphato group and/or a carboxyl group. Of these, 2-sulfobenzyl, 4-sulfobenzyl, 4-sulfophenethyl, 3-phenyl-3-sulfopropyl and 4-phenyl-4-sulfobutyl are most preferred.
When the methine dye of the general formula (IV), (V), (VI) or (VII) represents the chromophore represented by D1 of the general formula (III), the substituent represented by R17, R18, R19, R20, R21, R22, R23, R24 or R25 is preferably the above unsubstituted alkyl group or substituted alkyl group (for example, carboxyalkyl, sulfoalkyl, aralkyl or aryloxyalkyl).
When the methine dye of the general formula (IV), (V), (VI) or (VII) represents the chromophore represented by D2 of the general formula (III), the substituent represented by R17, R18, R19, R20, R21 R22, R23, R24 or R25 is preferably the unsubstituted alkyl group or substituted alkyl group, more preferably the alkyl group having an anionic substituent (e.g., carboxyalkyl or sulfoalkyl), and most preferably sulfoalkyl.
Each of L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15, L16, L17, L18, L19, L20, L21, L22, L23, L24, L25, L26, L27, L28, L29, L30, L31, L32, L33, L34, L35, L36, L37, L38, L39, L40, L41, L42, L43, L44, L45, L46, L47, L48, L49, L50, L51, L52, L53, L54, L55, L56, L57, L58, L59, L60, L61, L62, L63, L64, L65, L66 and L67 independently represents a methine group. The methine groups represented by L1 to L67 may have substituents, which can be those mentioned above as being represented by V. As such substituents, there can be mentioned, for example, a substituted or unsubstituted alkyl group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms (e.g., methyl, ethyl or 2-carboxyethyl), a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, preferably 6 to 15 carbon atoms, and more preferably 6 to 10 carbon atoms (e.g., phenyl or o-carboxyphenyl), a substituted or unsubstituted heterocyclic group having 3 to 20 carbon atoms, preferably 4 to 15 carbon atoms, and more preferably 6 to 10 carbon atoms (e.g., N,N-dimethylbarbituric acid group), a halogen atom (e.g., chlorine, bromine, iodine or fluorine), an alkoxy group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms (e.g., methoxy or ethoxy), an amino group having 0 to 15 carbon atoms, preferably 2 to 10 carbon atoms, and more preferably 4 to 10 carbon atoms (e.g., methylamino, N,N-dimethylamino, N-methyl-N-phenylamino or N-methylpiperadino), an alkylthio group having 1 to 15 carbon atoms, preferably 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms (e.g., methylthio or ethylthio), and an arylthio group having 6 to 20 carbon atoms, preferably 6 to 12 carbon atoms, and more preferably 6 to 10 carbon atoms (e.g., phenylthio or p-methylphenylthio). These may form rings in cooperation with other methine groups, or can form rings in cooperation with Z1 to Z25 and R1 to R25.
L1, L2, L3, L4, L5, L6, L10, L11, L12, L13, L16, L17, L23, L24, L25, L26, L30, L31, L32, L33, L36, L37, L43, L44, L45, L46, L50, L51, L52, L53, L56, L57, L63 and L64 preferably represent unsubstituted methine groups.
Each of n1, n2, n3, n4, n5, n6, n7, n8, n9, n10, n11, n12 and n13 is independently 0, 1, 2, 3 or 4, preferably 0, 1, 2 or 3, more preferably 0, 1 or 2, and most preferably 0 or 1. When n1, n2, n3, n4, n5, n6, n7, n8, n9, n10, n10, n12 and n13 are 2 or greater, methine groups are repeated, which are, however, not needed to be identical with each other.
Each of p1, p2, p3, p4, p5, p6, p7, p8, p9, p10, p11, p12, p13, p14, p15, p16 is independently 0 or 1, preferably 0.
M1, M2, M3, M4, M5 and M6, when required for neutralizing dye ion charges, are included in the formulae in order to indicate the presence of cations or anions. As representative cations, there can be mentioned inorganic cations such as proton (H+), alkali metal ions (e.g., sodium ion, potassium ion and lithium ion) and alkaline earth metal ions (e.g., calcium ion); and organic ions such as ammonium ions (e.g., ammonium ion, tetraalkylammonium ion, triethylammonium ion, pyridinium ion, ethylpyridinium ion and 1,8-diazabicyclo[5,4,0]-7-undecenium ion). The anions can be inorganic anions or organic anions. As such, there can be mentioned halide anions (e.g., fluoride ion, chloride ion and iodide ion), substituted arylsulfonate ions (e.g., p-toluenesulfonate ion and p-chlorobenzenesulfonate ion), aryldisulfonate ions (e.g., 1,3-benzenedisulfonate ion, 1,5-naphthalenedisulfonate ion and 2,6-naphthalenedisulfonate ion), alkylsulfate ions (e.g., methylsulfate ion), sulfate ion, thiocyanate ion, perchlorate ion, tetrafluoroborate ion, picrate ion, acetate ion and trifluoromethanesulfonate ion. Further, use can be made of ionic polymers and other dyes having charges opposite to those of dyes. CO2xe2x88x92 and SO3xe2x88x92, when having a proton as a counter ion, can be indicated as CO2H and SO3H, respectively.
Each of m1, m2, m3, m4, m5 and m6 is a number of 0 or greater required to balance a charge, preferably a number of 0 to 4, and more preferably a number of 0 to 1. When an intramolecular salt is formed, each is 0.
Only specific examples of the dyes for use in especially preferred technologies as described in detail in the description of embodiments of the present invention will now be set out, to which, however, the present invention is naturally in no way limited.
Specific examples of the compounds of the general formula (I) (including subordinate concept structures) according to the present invention:
Specific examples of the compounds of the general formula (II) (including subordinate concept structures) according to the present invention:
Specific examples of the compounds of the general formula (III) according to the present invention:
The dyes according to the present invention can be synthesized by the methods described in, for example, F. M. Harmer, xe2x80x9cHeterocyclic Compounds-Cyanine Dyes and Related Compoundsxe2x80x9d, John Wiley and Sons, New York, London, 1964; D. M. Sturmer, xe2x80x9cHeterocyclic Compounds-Special topics in heterocyclic chemistryxe2x80x9d, chapter 18, section 14, pages 482 to 515, John Wiley and Sons, New York, London, 1977; Rodd""s Chemistry of Carbon Compounds, 2nd. Ed. vol. IV, part B, 1977, chapter 15, pages 369 to 422, Elsevier Science Publishing Company Inc., New York; and the aforementioned patents and literature (cited for describing specific examples).
In the present invention, the sensitizing dyes are not limited to the above sensitizing dyes of the general formulae (I) to (III) (hereinafter also referred to as xe2x80x9csensitizing dye of the present inventionxe2x80x9d), and other sensitizing dyes can be used individually or in combination therewith. As preferably employed dyes, there can be mentioned, for example, a cyanine dye, a merocyanine dye, a rhodacyanine dye, a trinuclear merocyanine dye, a tetranuclear merocyanine dye, an allopolar dye, a hemicyanine dye and a styryl dye. A cyanine dye, a merocyanine dye and a rhodacyanine dye are more preferred. A cyanine dye is most preferred. Details of these dyes are described in, for example, F. M. Harmer, xe2x80x9cHeterocyclic Compounds-Cyanine Dyes and Related Compoundsxe2x80x9d, John Wiley and Sons, New York, London, 1964; and D. M. Sturmer, xe2x80x9cHeterocyclic Compounds-Special topics in heterocyclic chemistryxe2x80x9d, chapter 18, section 14, pages 482 to 515, John Wiley and Sons, New York, London, 1977.
As preferred dyes, further, there can be mentioned sensitizing dyes indicated by general formulae and specific examples listed on pages 32 to 44 of U.S. Pat. No. 5,994,051 and pages 30 to 39 of U.S. Pat. No. 5,747,236.
Further, as the general formulae for preferred cyanine, merocyanine and rhodacyanine dyes, there can be mentioned those shown in U.S. Pat. No. 5,340,694, columns 21 to 22, (XI), (XII) and (XIII) (wherein the numbers n12, n15, n17 and n18 are not limited as long as each of these is an integer of 0 or greater (preferably, 4 or less).
These sensitizing dyes can be used individually or in combination. Sensitizing dye combinations are often employed especially in order to attain supersensitization. Representative examples thereof are described in, for example, U.S. Pat. Nos. 2,688,545, 2,977,229, 3,397,060, 3,522,052, 3,527,641, 3,617,293, 3,628,964, 3,666,480, 3,672,898, 3,679,428, 3,303,377, 3,769,301, 3,814,609, 3,837,862 and 4,026,707, GB Nos. 1,344,281 and 1,507,803, Jpn. Pat. Appln. KOKOKU Publication No. (hereinafter referred to as JP-B-) 43-49336, JP-B-53-12375 and JP-A""s-52-110618 and 52-109925.
Together with these sensitizing dyes, dyes which have themselves no spectral sensitizing activity or substances which substantially do not absorb visible light and exhibit supersensitization may be contained in the emulsion.
Supersensitizing agents (for example, pyrimidylamino compounds, triazinylamino compounds, azolium compounds, aminostyryl compounds, aromatic organic acid/formaldehyde condensates, azaindene compounds and cadmium salts) and combinations of supersensitizing agent and sensitizing dye, which are useful in the spectral sensitization of the present invention, are described in, for example, U.S. Pat. Nos. 3,511,664, 3,615,613, 3,615,632, 3,615,641, 4,596,767, 4,945,038, 4,965,182, 2,933,390, 3,635,721, 3,743,510 and 3,617,295. With respect to the method of using these as well, those described in the above patents are preferred.
With respect to the timing of loading the silver halide emulsion of the present invention with the sensitizing dye of the present invention (same in the use of other sensitizing dyes and supersensitizing agents), it may be at any stage of the process for preparing the emulsion which has been recognized as being useful. For example, the loading may be performed at any stage prior to silver halide grain formation or/and desilvering or at any stage during desilvering and/or between completion of desilvering and initiation of chemical ripening, as disclosed in, for example, U.S. Pat. Nos. 2,735,766, 3,628,960, 4,183,756 and 4,225,666 and JP-A""s-58-184142 and 60-196749. Also, the loading may be performed at any stage immediately before chemical ripening or during chemical ripening or at any stage between completion of chemical ripening and emulsion coating, as disclosed in, for example, JP-A-58-113920. Moreover, as disclosed in, for example, U.S. Pat. No. 4,225,666 and JP-A-58-7629, a particular compound individually or in combination with other structurally different compounds may be divided into, for example, a portion to be added during grain formation and a portion to be added during chemical ripening or to be added after completion of chemical ripening, or into a portion to be added prior to or during chemical ripening and a portion to be added after chemical ripening, before the performing of the loading. In the performing of the loading, the type of compound and compound combination added in division may be changed.
The addition amount of sensitizing dye of the present invention (same in the use of other sensitizing dyes and supersensitizing agents), although varied depending on the configuration and size of silver halide grains, can be in the range of 1xc3x9710xe2x88x926 to 8xc3x9710xe2x88x923 mol per mol of silver halides. For example, when the size of silver halide grains is in the range of 0.2 to 1.3 xcexcm, the addition amount is preferably in the range of 2xc3x9710xe2x88x926 to 3.5xc3x9710xe2x88x923 mol, more preferably 7.5xc3x9710xe2x88x926 to 1.5xc3x9710xe2x88x923 mol, per mol of silver halides.
When the sensitizing dye of the present invention is adsorbed in multilayer form as aforementioned, the sensitizing dye is added in an amount needed to attain desired multilayer adsorption.
The sensitizing dye of the present invention (same in the use of other sensitizing dyes and supersensitizing agents) can directly be dispersed in the emulsion. Alternatively, the dispersion can be effected by first dissolving the sensitizing dye in an appropriate solvent such as methyl alcohol, ethyl alcohol, methylcellosolve, acetone, water, pyridine or a mixture thereof and adding the resultant solution to the emulsion. The dissolution can be conducted in the presence of additives such as a base, an acid and a surfactant. Also, in the dissolution, use can be made of ultrasonic vibration. The addition of these compounds can be accomplished by, for example, the method of dissolving such compounds in a volatile organic solvent, dispersing the solution into a hydrophilic colloid and adding the dispersion to the emulsion, as described in, for example, U.S. Pat. No. 3,469,987; the method of dispersing such compounds in a water-soluble solvent and adding the dispersion to the emulsion, as described in, for example, JP-B-46-24185; the method of dissolving such compounds in a surfactant and adding the solution to the emulsion, as described in, for example, U.S. Pat. No. 3,822,135; the method of dissolving such compounds with the use of a compound capable of effecting a red shift and adding the solution to the emulsion, as described in, for example, JP-A-51-74624; and the method of dissolving such compounds in an acid which substantially does not contain water and adding the solution to the emulsion, as described in, for example, JP-A-50-80826. Furthermore, the addition to the emulsion can be accomplished by, for example, the methods of U.S. Pat. Nos. 2,912,343, 3,342,605, 2,996,287 and 3,429,835.
In the present invention, it is preferred that photographically useful compounds as well as the sensitizing dye be adsorbed on silver halide grains. As such photographically useful compounds, there can be mentioned, for example, an antifoggant, a stabilizing agent and a nucleating agent. As the antifoggant and stabilizing agent, there can be employed, for example, compounds described in Research Disclosure (hereinafter referred to as RD), vol. 176, item 17643 (RD17643), vol. 187, item 18716 (RD18716), and vol. 308, item 308119 (RD308119). As the nucleating agent, there can be employed, for example, hydrazines described in U.S. Pat. Nos. 2,563,785 and 2,588,982; hydrazones and hydrazides described in U.S. Pat. No. 3,227,552; heterocyclic quaternary salt compounds described in, for example, GB No. 1,283,835, JP-A""s-52-69613, 55-138742, 60-11837, 62-210451 and 62-291637, and U.S. Pat. Nos. 3,615,515, 3,719,494, 3,734,738, 4,094,683, 4,115,122, 4,306,016 and 4,471,044; sensitizing dyes having a substituent with nucleating activity in dye molecules, described in U.S. Pat. No. 3,718,470; thiourea-bonded acylhydrazine compounds described in, for example, U.S. Pat. Nos. 4,030,925, 4,031,127, 4,245,037, 4,255,511, 4,266,013 and 4,276,364 and GB No. 2,012,443; and acylhydrazine compounds having a thioamido ring or a heterocyclic group, such as triazolyl or tetrazolyl, bonded thereto as an adsorptive group, described in, for example, U.S. Pat. Nos. 4,080,270 and 4,278,748 and GB No. 2,011,391B.
As photographically useful compounds preferred in the present invention, there can be mentioned nitrogenous heterocyclic compounds such as thiazole and benzotriazole, mercapto compounds, thioether compounds, sulfinic acid compounds, thiosulfonic acid compounds, thioamide compounds, urea compounds, selenourea compounds and thiourea compounds of these, nitrogenous heterocyclic compounds, mercapto compounds, thioether compounds and thiourea compounds are more preferred. Nitrogenous heterocyclic compounds are most preferred. The nitrogenous heterocyclic compounds are preferably those of the general formulae (VII) to (X).
Although the addition of photographically useful compounds can be conducted prior to, or after, or during the loading of sensitizing dye, it is preferred that the addition of photographically useful compounds be performed prior to or during the loading of sensitizing dye. It is more preferred that the addition be performed during the loading of sensitizing dye.
The addition amount of photographically useful compounds, although varied depending on the function of additive and the type of emulsion, is typically in the range of 1xc3x9710xe2x88x926 to 5xc3x9710xe2x88x923 mol/mol Ag.
In the photographic emulsion which engages in lightsensitive mechanism in the present invention, although all of silver bromide, silver iodobromide, silver chlorobromide, silver iodide, silver iodochloride, silver iodobromochloride and silver chloride can be used as silver halides, a highly secure multilayer adsorption structure can be constructed by causing the halide composition of emulsion outermost surface to contain 0.1 mol % or more, preferably 1 mol % or more, and more preferably 5 mol % or more, of iodide.
Although the grain size distribution may be broad or narrow, a narrow distribution is preferred.
The silver halide grains of photographic emulsion, although may consist of those having a regular crystal form such as a cube, an octahedron, a tetradecahedron or a rhombic dodecahedron, those having an irregular crystal form such as a spherical or platelike shape, those having high-order faces ((hkl) faces) or those composed of a mixture of grains with these crystal forms, preferably consist of tabular grains. Tabular grains will be described in detail below. With respect to grains with high-order faces, reference can be made to pages 247 to 254 of Journal of Imaging Science, vol. 30 (1986).
These silver halide grains, individually or in mixture, may be contained in the silver halide photographic emulsion for use in the present invention. The silver halide grains may have phases which are different between the internal part and the surface layer, or may have a multilayer structure with a junction structure, or may have a phase localized at grain surfaces, or may have a phase which is uniform through the entirety of grains. These may be present in mixture. These various emulsions may be of the surface latent image type wherein latent images are primarily formed on grain surfaces, or may be of the internal latent image type wherein latent images are primarily formed in the internal part of grains.
The silver halide emulsion for use in the present invention preferably consists of tabular silver halide grains exhibiting a high ratio of surface area/volume, wherein the sensitizing dye disclosed in the present invention is adsorbed on grains. These tabular silver halide grains preferably have an aspect ratio of 2 to 100, more preferably 5 to 80, and most preferably 8 to 80. The thickness of these tabular silver halide grains is preferably less than 0.2 xcexcm, more preferably less than 0.1 xcexcm, and most preferably less than 0.07 xcexcm. The following technology can be utilized for the preparation of these thin tabular grains of high aspect ratio.
In the present invention, tabular silver halide grains whose halide composition is silver chloride, silver bromide, silver chlorobromide, silver iodobromide, silver chloroiodobromide or silver iodochloride are preferably employed. Tabular grains having (100) or (111) principal surfaces are preferred. Tabular grains having (111) principal surfaces (hereinafter referred to as (111) tabular grains) generally have trigonal or hexagonal surfaces. Generally, when the distribution becomes narrow, the ratio of tabular grains with hexagonal surfaces would be increased. Hexagonal monodispersed tabular grains are described in JP-B-5-61205.
Tabular grains having (100) faces as principal surfaces (hereinafter referred to as (100) tabular grains) have rectangular or square shapes. In the emulsion, grains of from needle (acicular) grains to grains of less than 5:1 neighboring side ratio are referred to as tabular grains. With respect to the tabular grains of silver chloride or containing silver chloride in high ratio, the stability of principal surfaces is inherently higher in the (100) tabular grains than in the (111) tabular grains. In the use of (111) tabular grains, it is required to stabilize the (111) principal surfaces. With respect to this matter, reference can be made to JP-A""s 9-80660 and 9-80656 and U.S. Pat. No. 5,298,388.
The (111) tabular grains of silver chloride or exhibiting a high silver chloride content for use in the present invention are disclosed in the following patents.
Namely, U.S. Pat. Nos. 4,414,306, 4,400,463, 4,713,323, 4,783,398, 4,962,491, 4,983,508, 4,804,621, 5,389,509, 5,217,858 and 5,460,934.
The (111) tabular grains of high silver bromide content for use in the present invention are described in the following patents.
Namely, U.S. Pat. Nos. 4,425,425, 4,425,426, 443,426, 4,439,520, 4,414,310, 4,433,048, 4,647,528, 4,665,012, 4,672,027, 4,678,745, 4,684,607, 4,593,964, 4,722,886, 4,755,617, 4,755,456, 4,806,461, 4,801,522, 4,835,322, 4,839,268, 4,914,014, 4,962,015, 4,977,074, 4,985,350, 5,061,609, 5,061,616, 5,068,173, 5,132,203, 5,272,048, 5,334,469, 5,334,495, 5,358,840 and 5,372,927.
The (100) tabular grains for use in the present invention are described in the following patents. Namely, U.S. Pat. Nos. 4,386,156, 5,275,930, 5,292,632, 5,314,798, 5,320,938, 5,319,635 and 5,356,764; EP Nos. 569,971 and 737,887; and JP-A""s-6-308648 and 9-5911.
The silver halide emulsion is generally chemically sensitized before use. In the chemical sensitization, chalcogen sensitization (sulfur sensitization, selenium sensitization or tellurium sensitization), noble metal sensitization (e.g., gold sensitization) and reduction sensitization are carried out individually or in combination.
In the present invention, the silver halide emulsion having undergone at least selenium sensitization is preferred. That is, selenium sensitization only, or selenium sensitization in combination with chalcogen sensitization and/or noble metal sensitization (especially, gold sensitization) is preferred. A combination of selenium sensitization and noble metal sensitization is especially preferred.
In the selenium sensitization, unstable selenium compounds are used as a sensitizing agent. Unstable selenium compounds are described in JP-B""s-43-13489 and 44-15748 and JP-A""s-4-25832, 4-109240, 4-271341 and 5-40324. Examples of suitable selenium sensitizing agents include colloidal metallic selenium, selenoureas (e.g., N,N-dimethylselenourea, trifluoromethylcarbonyl-trimethylselenourea and acetyl-trimethylselenourea), selenoamides (e.g., selenoacetamide and N,N-diethylphenylselenoamide), phosphine selenides (e.g., triphenylphosphine selenide and pentafluorophenyl-triphenylphosphine selenide), selenophosphates (e.g., tri-p-tolyl selenophosphate and tri-n-butyl selenophosphate), selenoketones (e.g., selenobenzophenone), isoselenocyanates, selenocarboxylic acids, selenoesters and diacyl selenides. Further, relatively stable selenium compounds such as selenious acid, potassium selenocyanide, selenazoles and selenides (described in JP-B""s-46-4553 and 52-34492) can also be used as the selenium sensitizing agent.
In the sulfur sensitization, unstable sulfur compounds are used as a sensitizing agent. Unstable sulfur compounds are described in P. Glafkides, xe2x80x9cChemie et Physique Photographiquexe2x80x9d, Paul Montel, 5th ed., 1987 and Research Disclosure, vol. 307, item 307105. Examples of suitable sulfur sensitizing agents include thiosulfates (e.g., hypo), thioureas (e.g., diphenylthiourea, triethylthiourea, N-ethyl-Nxe2x80x2-(4-methyl-2-thiazolyl)thiourea and carboxymethyltrimethylthiourea), thioamides (e.g., thioacetamide), rhodanines (e.g., diethylrhodanine and 5-benzylidene-N-ethyl-rhodanine), phosphine sulfides (e.g., trimethylphosphine sulfide), thiohydantoins, 4-oxazolidine-2-thiones, dipolysulfides (e.g., dimorpholine disulfide and cystine), mercapto compounds (e.g., cysteine), polythionic acid salts and elemental sulfur. Also, active gelatin can be used as a sulfur sensitizing agent.
In the tellurium sensitization, unstable tellurium compounds are used as a sensitizing agent. Unstable tellurium compounds are described in CA No. 800,958, GB Nos. 1,295,462 and 1,396,696, and JP-A""s-4-204640, 4-271341, 4-333043 and 5-303157. Examples of suitable tellurium sensitizing agents include telluroureas (e.g., tetramethyltellurourea, N,Nxe2x80x2-dimethylethylenetellurourea and N,Nxe2x80x2-diphenylethylenetellurourea), phosphine tellurides (e.g., butyl-diisopropylphosphine telluride, tributylphosphine telluride, tributoxyphosphine telluride and ethoxy-diphenylphosphine telluride), diacyl (di)tellurides (e.g., bis(diphenylcarbamoyl) ditelluride, bis(N-phenyl-N-methylcarbamoyl) ditelluride, bis(N-phenyl-N-methylcarbamoyl) telluride and bis(ethoxycarbonyl) telluride), isotellurocyanates, telluroamides, tellurohydrazides, telluroesters (e.g., butylhexyl telluoroester), telluroketones (e.g., telluroacetophenone), colloidal tellurium, (di)tellurides and other tellurium compounds (e.g., potassium telluride and sodium telluropentathionate).
In the noble metal sensitization, salts of noble metals such as gold, platinum, palladium and iridium are used as a sensitizing agent. Nobel metal salts are described in P. Glafkides, xe2x80x9cChemie et Physique Photographiquexe2x80x9d, Paul Montel, 5th ed., 1987 and Research Disclosure, vol. 307, item 307105. Gold sensitization is especially preferred. As aforementioned, the present invention is especially effective in embodiments wherein the gold sensitization is carried out.
That gold can be removed from sensitized nuclei on emulsion grains with the use of a solution containing potassium cyanide (KCN) is described in Photographic Science and Engineering, vol. 19322 (1975) and Journal of Imaging Science, vol. 3228 (1988). As described therein, cyanide ions liberate gold atoms or gold ions adsorbed on silver halide grains as a cyanide complex to thereby inhibit the gold sensitization. Suppressing the formation of cyanide according to the present invention enables satisfactory exertion of the effect of gold sensitization.
Examples of suitable gold sensitizing agents include chloroauric acid, potassium chloroaurate, potassium aurithiocyanate, gold sulfide and gold selenide. Also, use can be made of gold compounds described in the specifications of U.S. Pat. Nos. 2,642,361, 5,049,484 and 5,049,485.
In the reduction sensitization, reducing compounds are used as a sensitizing agent. Reducing compounds are described in P. Glafkides, xe2x80x9cChemie et Physique Photographiquexe2x80x9d, Paul Montel, 5th ed., 1987 and Research Disclosure, vol. 307, item 307105. Examples of suitable reduction sensitizing agents include aminoiminomethanesulfinic acid (thiourea dioxide), borane compounds (e.g., dimethylaminoborane), hydrazine compounds (e.g., hydrazine and p-tolylhydrazine), polyamine compounds (e.g., diethylenetriamine and triethylenetetramine), stannous chloride, silane compounds, reductones (e.g., ascorbic acid), zinc sulfite, aldehyde compounds and hydrogen gas. The reduction sensitization can be effected in an atmosphere of high pH or silver ion excess (namely, silver ripening). The reduction sensitization is preferably carried out during the formation of silver halide grains.
The addition amount of sensitizing agent is generally determined depending on the type of employed silver halide grains and the conditions of chemical sensitization.
The addition amount of chalcogen sensitizing agent is generally in the range of 10xe2x88x928 to 10xe2x88x922 mol, preferably 10xe2x88x927 to 5xc3x9710xe2x88x923 mol, per mol of silver halides.
The addition amount of noble metal sensitizing agent is preferably in the range of 10xe2x88x927 to 10xe2x88x922 mol per mol of silver halides.
Although the conditions of chemical sensitization are not particularly limited, the pAg is generally in the range of 6 to 11, preferably 7 to 10. It is preferred that the pH range from 4 to 10. The temperature is preferably in the range of 40 to 95xc2x0 C., more preferably 45 to 85xc2x0 C.
The additives are described in detail in RD Item 17643 (December 1978), Item 18716 (November 1979) and Item 308119 (December 1989). A summary of the locations where they are described will be listed in the following table.
With respect to the emulsion of the present invention and with respect to the layer arrangement and related techniques, silver halide emulsions, dye forming couplers, DIR couplers and other functional couplers, various additives and development processing, which can be employed for the photographic lightsensitive material including the emulsion, reference can be made to EP No.0565096A1 (published on Oct. 13, 1993) and patents cited therein. Individual particulars and the locations where they are described will be listed below.
Layer arrangement: page 61 lines 23 to 35, page 61 line 41 to page 62 line14,
Interlayers: page 61 lines 36 to 40,
Interlayer effect imparting layers: page 62 lines 15 to 18,
Silver halide halogen compositions: page 62 lines 21 to 25,
Silver halide grain crystal habits: page 62 lines 26 to 30,
Silver halide grain sizes: page 62 lines 31 to 34,
Emulsion production methods: page 62 lines 35 to 40,
Silver halide grain size distributions: page 62 lines 41 to 42,
Tabular grains: page 62 lines 43 to 46,
Internal structures of grains: page 62 lines 47 to 53,
Latent image forming types of emulsions: page 62 line 54 to page 63 to line 5,
Physical ripening and chemical sensitization of emulsion: page 63 lines 6 to 9,
Emulsion mixing: page 63 lines 10 to 13,
Fogging emulsions: page 63 lines 14 to 31,
Nonlightsensitive emulsions: page 63 lines 32 to 43,
Silver coating amounts: page 63 lines 49 to 50,
Formaldehyde scavengers: page 64 lines 54 to 57,
Mercapto antifoggants: page 65 lines 1 to 2,
Fogging agent, etc. release agents: page 65 lines 3 to 7,
Dyes: page 65, lines 7 to 10,
Color coupler summary: page 65 lines 11 to 13,
Yellow, magenta and cyan couplers: page 65 lines 14 to 25,
Polymer couplers: page 65 lines 26 to 28,
Diffusive dye forming couplers: page 65 lines 29 to 31,
Colored couplers: page 65 lines 32 to 38,
Functional coupler summary: page 65 lines 39 to 44,
Bleaching accelerator release couplers: page 65 lines 45 to 48,
Development accelerator release couplers: page 65 lines 49 to 53,
Other DIR couplers: page 65 line 54 to page 66 to line 4,
Method of dispersing couplers: page 66 lines 5 to 28,
Antiseptic and mildewproofing agents: page 66 lines 29 to 33,
Types of sensitive materials: page 66 lines 34 to 36,
Thickness of lightsensitive layer and swell speed: page 66 line 40 to page 67 line 1,
Back layers: page 67 lines 3 to 8,
Development processing summary: page 67 lines 9 to 11,
Developers and developing agents: page 67 lines 12 to 30,
Developer additives: page 67 lines 31 to 44,
Reversal processing: page 67 lines 45 to 56,
Processing solution open ratio: page 67 line 57 to page 68 line 12,
Development time: page 68 lines 13 to 15,
Bleach-fix, bleaching and fixing: page 68 line 16 to page 69 line 31,
Automatic processor: page 69 lines 32 to 40,
Washing, rinse and stabilization: page 69 line 41 to page 70 line 18,
Processing solution replenishment and recycling: page 70 lines 19 to 23,
Containment of developing agent in sensitive material: page 70 lines 24 to 33,
Development processing temperature: page 70 lines 34 to 38, and
Application to film with lens: page 70 lines 39 to 41.
Couplers for use in the present invention can be introduced in the lightsensitive material by various known dispersing methods. Examples of high-boiling solvents for use in the in-water oil droplet dispersing method are described in, for example, U.S. Pat. No. 2,322,027. As specific examples of high-boiling organic solvents having a boiling point of 175xc2x0 C. or higher at atmospheric pressure for use in the in-water oil droplet dispersing method, there can be mentioned phthalic acid esters (e.g., dibutyl phthalate, dicyclohexyl phthalate, di-2-ethylhexyl phthalate, decyl phthalate, bis(2,4-di-t-amylphenyl) phthalate, bis(2,4-di-t-amylphenyl) isophthalate and bis(1,1-diethylpropyl) phthalate), esters of phosphoric acid or phosphonic acid (e.g., triphenyl phosphate, tricresyl phosphate, 2-ethylhexyldiphenyl phosphate, tricyclohexyl phosphate, tri-2-ethylhexyl phosphate, tridecyl phosphate, tributoxyethyl phosphate, trichloropropyl phosphate and di-2-ethylhexylphenyl phosphonate), benzoic acid esters (e.g., 2-ethylhexyl benzoate, dodecyl benzoate and 2-ethylhexyl p-hydroxybenzoate), amides (e.g., N,N-diethyldodecanamide, N,N-diethyllaurylamide and N-tetradecylpyrrolidone), alcohols or phenols (e.g., isostearyl alcohol and 2,4-di-tert-amylphenol), aliphatic carboxylic acid esters (e.g., bis(2-ethylhexyl) sebacate, dioctyl azelate, glycerol tributylate, isostearyl lactate and trioctyl citrate), aniline derivatives (e.g., N,N-dibutyl-2-butoxy-5-tert-octylaniline), and hydrocarbons (e.g., paraffin, dodecylbenzene and diisopropylnaphthalene). Further, as auxiliary solvents, there can be used, for example, organic solvents having a boiling point of about 30xc2x0 C. or higher, preferably about 50 to about 160xc2x0 C. Representative examples thereof include ethyl acetate, butyl acetate, ethyl propionate, methyl ethyl ketone, cyclohexanone, 2-ethoxyethyl acetate and dimethylformamide.
Steps of the latex dispersing method, the effect thereof and specific examples of impregnation latexes are described in, for example, U.S. Pat. No. 4,199,363 and OLS (German patent application) Nos. 2,541,274 and 2,541,230.
Further, the solid dispersing method described in WO No. 88/4794 can be applied.
In the present invention, the specified photographic speed defined and described in detail below is employed for indicating the sensitivity of photographic lightsensitive material. The reason therefor is as follows.
Generally, the ISO speed being international standards is employed for indicating the sensitivity of photographic lightsensitive material. In connection with the ISO speed, it is stipulated that lightsensitive materials are to be developed on the fifth day after exposure, and that the development is to be performed by the processing specified by each company concerned. Thus, in the present invention, the following specified photographic speed is employed so as to shorten the period from completion of exposure to initiation of development (0.5 to 6 hours) and so as to determine the speed through established development processing.
The specified photographic speed of lightsensitive material referred to in the present invention is determined by the following test method according to the ISO speed (in accordance with JIS K 7614-1981).
(1) Testing conditions:
The test is performed in a room of 20xc2x15xc2x0 C. temperature and 60xc2x110% relative humidity. Every lightsensitive material specimen is allowed to stand still in this state for at least one hour before use.
(2) Exposure:
(i) The relative spectral energy distribution of reference light on exposed surface is as specified in table A.
(ii) Illuminance variation on exposed surface is effected with the use of an optical wedge. Employed optical wedge is such that, at any portion thereof, the variation of spectral transmission density, in a wavelength range of 360 to 700 nm, is within 10% in a less than 400 nm region and within 5% in a 400 nm or more range.
(iii) Exposure time is {fraction (1/100)} sec.
(3) Development processing:
(i) During the period from exposure to development processing, the lightsensitive material specimen is held in an atmosphere of 20xc2x15xc2x0 C. temperature and 60xc2x110% relative humidity.
(ii) The development processing is completed within 30 min to 6 hr of the exposure.
(iii) The development processing is performed through the following steps.
The composition of processing solution for use in each of the above steps is as follows:
(4) Density measurement:
The density is expressed by log10 ("PHgr"0/"PHgr"). "PHgr"0 represents a lighting luminous flux for density measurement, and "PHgr" represents a transmitted luminous flux at each part to be measured. With respect to geometrical conditions for density measurement, it is standard to use parallel luminous flux to the normal direction as a lighting luminous flux and to use total luminous flux having been transmitted and extended over a half space as a transmitted luminous flux. When the density measurement is otherwise conducted, a correction by a standard density piece is effected. Further, after the measurement, each emulsion film surface is arranged opposite to a photoreceptor side. The density measurement is effected in terms of blue, green and red status M densities, and the spectral characteristics thereof are so made as to exhibit values listed in Table B as collective properties of light source used for densitometer, optical system, optical filter and phtotoreceptor.
(5) Determination of specified photographic speed:
The specified photographic speed is determined from the results of processing and density measurement performed under conditions indicated in items (1) to (4) above in accordance with the following procedure.
(i) The exposure quantities corresponding to densities 0.15 higher than minimum densities with respect to blue, green and red are expressed in terms of luxxc2x7sec and referred to as HB, HG and HR, respectively.
(ii) Of HB and HR, one of higher value (one of lower speed) is referred to as HS.
(iii) The specified photographic speed S is calculated using the formula A:
S={2/(HGxc3x97HS)}1/2.
With respect to the lightsensitive material of the present invention, it is preferred that the specified photographic speed determined in the above procedure be 320 or more. As apparent from the following experimental results, at specified photographic speeds of less than 320, not only is it practically impossible to conduct photographing in a dark room without the use of any strobe, high speed shutter photographing with the use of telephotographic lens for, for example, sports photographs and photographing for astronomical photographs, but also the probability of failure, such as out of focus or under-exposure, at ordinary photographing would be increased.
With respect to the lightsensitive material of the present invention, it is more preferred that the specified photographic speed be 350 or more.
The amount of silver contained in common lightsensitive materials is in the range of 3.0 to 8.0 g/m2. With respect to commercially available high-speed color negative films whose speed is 320 or more, it is common practice in the art to which the present invention pertains to set the silver content for a high level in order to enhance the sensitivity and graininess, as described in, for example, JP-A-58-147744. However, when the silver content is over 8.0 g/m2, such a level of graininess deterioration as to invite practical problems would be caused by exposure to natural radiation for about half a year to two years. Surprisingly, the graininess deterioration by natural radiation has greatly been relieved by reducing the silver content to 8.0 g/m2 or less. Furthermore, although the enhancement of sharpness and color reproducibility by reducing the silver content has been expected to a certain extent, the degree of the enhancement has been far greater than the expectation. On the other hand, at the silver content of less than 3.0 g/m2, it has been impossible to attain the maximum density required for color negative lightsensitive materials.
The terminology xe2x80x9csilver contentxe2x80x9d used herein means the amount in terms of silver of all silver substances including silver halides and metallic silver. Some methods are known for the analysis of the silver content of lightsensitive materials, and any of them can be employed. For example, the fluorescent X-ray method is simple and easy.
The lightsensitive material produced using the emulsion of the present invention is preferably one having at least one lightsensitive layer constituted by a plurality of silver halide emulsion layers which have the same color sensitivity but exhibit different photographic speeds. This lightsensitive layer consists of a unit lightsensitive layer which is sensitive to any of blue light, green light and red light. In a multilayered silver halide color photographic lightsensitive material, these unit lightsensitive layers are generally arranged in the order of red-, green- and blue-sensitive layers from a support side. However, according to the intended use, this arrangement order may be reversed, or an arrangement order can be employed in which a different lightsensitive layer is interposed between the layers of the same color sensitivity.
Nonlightsensitive layers can be formed between the silver halide lightsensitive layers and as the uppermost layer and the lowermost layer. These may contain, e.g., couplers, DIR compounds and color mixing inhibitors described later. As a plurality of silver halide emulsion layers constituting each unit lightsensitive layer, a two-layered structure of high- and low-speed emulsion layers is preferably arranged so that the sensitivity is sequentially decreased toward a support as described in DE No. 1,121,470 or GB No. 923,045. Also, as described in JP-A-57-112751, JP-A-62-200350, JP-A-62-206541 and JP-A-62-206543, layers can be arranged so that a low-speed emulsion layer is formed on a side apart from a support while a high-speed emulsion layer is formed on a side close to the support.
Specifically, layers can be arranged, from the farthest side from a support, in the order of low-speed blue-sensitive layer (BL)/high-speed blue-sensitive layer (BH)/high-speed green-sensitive layer (GH)/low-speed green-sensitive layer (GL)/high-speed red-sensitive layer (RH)/low-speed red-sensitive layer (RL), the order of BH/BL/GL/GH/RH/RL or the order of BH/BL/GH/GL/RL/RH.
In addition, as described in JP-B-55-34932, layers can be arranged, from the farthest side from a support, in the order of blue-sensitive layer/GH/RH/GL/RL. Furthermore, as described in JP-A-56-25738 and JP-A-62-63936, layers can be arranged, from the farthest side from a support, in the order of blue-sensitive layer/GL/RL/GH/RH.
As described in JP-B-49-15495, three layers can be arranged so that a silver halide emulsion layer having the highest sensitivity is arranged as an upper layer, a silver halide emulsion layer having sensitivity lower than that of the upper layer is arranged as an interlayer, and a silver halide emulsion layer having sensitivity lower than that of the interlayer is arranged as a lower layer; i.e., three layers having different sensitivities can be arranged so that the sensitivity is sequentially decreased toward the support. Even when a layer structure is constituted by three layers having different sensitivities as mentioned above, these layers can be arranged in the order of medium-speed emulsion layer/high-speed emulsion layer/low-speed emulsion layer from the farthest side from a support in a layer sensitive to one color as described in JP-A-59-202464.
In addition, the order of high-speed emulsion layer/low-speed emulsion layer/medium-speed emulsion layer or low-speed emulsion layer/medium-speed emulsion layer/high-speed emulsion layer can be adopted. Furthermore, the arrangement can be changed as described above even when four or more layers are formed.
The lightsensitive material of the present invention, in one embodiment, has at least one red-sensitive silver halide emulsion layer, at least one green-sensitive silver halide emulsion layer and at least one blue-sensitive silver halide emulsion layer. It is preferred that any emulsion layers with identical color sensitivity comprise a plurality of emulsion layers whose speeds are different from each other. It is more preferred that a three-layer structure be constructed from the viewpoint of graininess improvement. These technologies are described in GB No. 923,045 and JP-B-49-15495.
In the field of color negative photographic lightsensitive material, for obtaining a color negative photographic lightsensitive material of high image quality, it is common practice to adopt a design such that, when emulsion layers with identical color sensitivity are composed of a plurality of emulsion layers whose speeds are different from each other, high-speed emulsion layers have high silver contents in order to utilize what is known as a graininess vanishing effect. However, an unexpected disadvantage such that, in high-speed color negative photographic lightsensitive materials of 320 or more specified photographic speed, increasing the silver content of high-speed emulsion layer aggravates the performance deterioration with the passage of time during storage as compared with an increase of the silver content of low-speed emulsion layer has become apparent. Therefore, it is preferred that the silver content of the highest-speed emulsion layer among emulsion layers with identical color sensitivity be not much high. The silver content of the highest-speed emulsion layer of the red-sensitive emulsion layers, green-sensitive emulsion layers or blue-sensitive emulsion layers is preferably in the range of 0.1 to 1.8 g/m2, more preferably 0.1 to 1.6 g/m2, and most preferably 0.1 to 1.4 g/m2.
In the use of the silver halide emulsion of the present invention, the multilayer adsorption enables realizing a speed increase. Thus, in the designing of a silver halide photographic lightsensitive material with the use of the silver halide emulsion, not only, by virtue of the high speed, can the grain size be reduced to thereby enable producing a lightsensitive material with highly excellent graininess but also the silver content of silver halide emulsion layer can be reduced to thereby enable designing a silver halide photographic lightsensitive material whose performance deterioration with the passage of time during storage is relieved. Practically, the amount of silver contained in the lightsensitive material of the present invention can be reduced so as to be in the range of 0.1 to 7.0 g/m2. When the above specified photographic speed is 320 or over, designing can be made so that the amount of silver contained is further reduced so as to be in the range of 0.1 to 6.0 g/m2.